65th IHC Booklet/Program (pdf - 4.9MB) - Office of the Federal ...

65th Interdepartmental 

Hurricane Conference 

Miami, Florida 

February 28 - March 3, 2011 

Hurricane Earl:September 2, 2010 

Ocean and Atmospheric Influences on Tropical 

Cyclone Predictions: Challenges and Recent 

Progress

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Session 2 

The 2010 Tropical Cyclone 

Season in Review 

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The 2010 Atlantic Hurricane Season: 

Extremely Active but no U.S. Hurricane Landfalls 

Eric Blake and John L. Beven II 

(Eric.S.Blake@noaa.gov) 

NOAA/NWS/National Hurricane Center 

The 2010 Atlantic hurricane season was quite active, with 19 named storms, 12 of which 

became hurricanes and 5 of which reached major hurricane intensity. These totals are well above 

the long-term normals of about 11 named storms, 6 hurricanes, and 2 major hurricanes. 

Although the 2010 season was considerably busier than normal, no hurricanes struck the United 

States. This was the most active season on record in the Atlantic that did not have a U.S. 

landfalling hurricane, and was also the second year in a row without a hurricane striking the U.S. 

coastline. A persistent trough along the east coast of the United States steered many of the 

hurricanes out to sea, while ridging over the central United States kept any hurricanes over the 

western part of the Caribbean Sea and Gulf of Mexico farther south over Central America and 

Mexico. 

The most significant U.S. impacts occurred with Tropical Storm Hermine, which brought 

hurricane-force wind gusts to south Texas along with extremely heavy rain, six fatalities, and 

about $240 million dollars of damage. Hurricane Earl was responsible for four deaths along the 

east coast of the United States due to very large swells, although the center of the hurricane 

stayed offshore. 

Session 2 – Page 1

Overview of the 2010 Eastern North Pacific Hurricane Season 

John P. Cangialosi and Stacy R. Stewart 

(John.P.Cangialosi@noaa.gov and Stacy.R.Stewart@noaa.gov ) 

NOAA/NWS Tropical Prediction Center/National Hurricane Center 

The 2010 eastern North Pacific hurricane season was historically the least active on record. Only 

seven tropical storms developed, three of which became hurricanes. This is the lowest number 

of tropical storms and hurricanes observed since routine satellite reconnaissance of the basin 

began in 1971. Five tropical depressions formed this season that did not strengthen into tropical 

storms. The Accumulated Cyclone Energy (ACE) index for 2010 was 46% of the long-term 

median. This is the third lowest ACE value, ahead of only the 2007 and 1997 seasons. 

Although the season was inactive, Tropical Storm Agatha was a high impact event causing 160 

deaths and significant damage to portions of Central America and Mexico. This, along with 

other season highlights will be presented. In addition, some of the operational challenges 

encountered during the season will also be discussed. 


2010 Atlantic and Eastern North Pacific 

Forecast Verification 

James L. Franklin 

(james.franklin@noaa.gov) 

NOAA/NWS/National Hurricane Center 

A verification of official track, intensity, and genesis forecasts from the National 

Hurricane Center during the 2010 season will be presented, along with a discussion of the 

performance of the guidance models. 


Review of the 2010 Central Pacific Tropical Cyclone Season and Preliminary Verification 

Raymond Tanabe 

(raymond.tanabe@noaa.gov) 

Deputy Director, Central Pacific Hurricane Center (CPHC) 

In 2010, there was one tropical cyclone to have formed in or moved into the central Pacific. 

Tropical Storm Omeka originated as a subtropical storm west of the dateline and transitioned 

into a tropical cyclone just east of the dateline on 20 December 2010. CPHC will present an 

overview of Tropical Storm Omeka, the preliminary verification, changes for the 2011 season, 

and recent staff changes. 


A Review of the Joint Typhoon Warning Center 

2010 Tropical Cyclone Season 

Mr. Robert J. Falvey 

(robert.falvey@navy.mil) 

Joint Typhoon Warning Center 

A review of the 2010 tropical cyclone activity with discussion of significant events for the JTWC 

Pacific and Indian Ocean forecast areas of responsibility will be presented. 


53d Weather Reconnaissance Review of the 2010 Hurricane Season 

Capt Douglas Gautrau 

(Douglas.Gautrau.1@us.af.mil) 

53d Weather Reconnaissance Squadron 

The 2010 hurricane season was a slightly below average year for the 53d Weather 

Reconnaissance Squadron with 981.4 total flying hours (compared to 1062 average flying hours 

per season over the previous 10 years). Although the storm season seemed relatively slow due to 

the lack of storms in the Gulf of Mexico, we stayed very busy flying the majority of our flights in 

the Caribbean Sea and Atlantic Ocean. We flew a total of 100 tasked missions meeting 97% of 

our requirements. 

Overall, the Stepped Frequency Microwave Radiometer once again performed 

reasonably well on ten WC-130J aircraft, providing critical surface wind speed and rainfall rate 

data to the customer. Operator experience increased with the instrument and valuable inputs and 

improvements to instrument performance were accomplished. 


NOAA Aircraft Operations Center (AOC) 

2010 Seasonal Summary and Future Plans 

Jim McFadden, Nancy Ash, Jack Parrish, Paul Flaherty, A. Barry Damiano, Ian Sears, 

Jessica Williams, Richard Henning 

(Jim.d.mcfadden@noaa.gov) 

NOAA Aircraft Operations Center 

After a relatively slow season in 2009, during which NOAA aircraft flew a total of 62 flights and 

326 hrs, the 2010 season was a bit more active with its three hurricane aircraft, two WP-3Ds and 

the Gulfstream G-IV, flying 71 flights for 453 hours. These flights, in addition to storm flights, 

included trips for public awareness, such as the Gulf Coast Hurricane Awareness Tour and the 

Governor’s Hurricane Conference, test and calibration flights as well as several transit flights. 

Of significance during the 2010 season was the joint NASA, NOAA and NSF operation that 

utilized a number of aircraft from each of the Agencies in a study of tropical storm genesis and 

rapid intensification. In addition to NOAA’s three aircraft, NASA provided its DC-8, aWB-57 

and Global Hawk. The NSF provided the Gulfstream G-V. These aircraft often flew 

coordinated patterns associated with tropical systems in the Atlantic and Caribbean. The three 

NOAA aircraft also obtained the most comprehensive data set on the development and decay of 

a tropical system when they flew Hurricane Earl practically from the cradle to the grave – from 

genesis to extra-tropical transition. 

AOC continues to upgrade its aircraft and instrumentation, and in 2011 expects to accomplish 

the following: 

• Complete the acceptance tests of the tail Doppler radar on the NOAA G-IV 

• Continue developing strategies for use of the new G-IV TDR in storm environment 

• Complete the avionics upgrade on N44RF, NOAA’s 3 rd P-3 

• Complete integration of new aircraft data system (AAMPS) on the NOAA P-3s 

• Complete installation of new AXBT receivers on both P-3s 


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Session 3 

Observations and 

Observing Strategies for 

Tropical Cyclones and 

their Environment, Part 1 

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Microwave sounder observations during GRIP: Preliminary results 

Bjorn Lambrigtsen, Shannon Brown 

(lambrigtsen@jpl.nasa.gov) 

Jet Propulsion Laboratory, California Institute of Technology 

The High Altitude MMIC Sounding Radiometer (HAMSR), a microwave sounder similar to but 

more advanced than the AMSU sounders now operating on multiple satellites, was deployed on 

the Global Hawk unmanned aircraft during the Genesis and Rapid Intensification Processes 

(GRIP) hurricane field campaign during August and September 2010. HAMSR was developed at 

the Jet Propulsion Laboratory more than ten years ago and has been flown in several hurricane 

field campaigns. It was recently upgraded with the latest technology and is now the most 

sensitive and accurate sensor of its kind. Using observations from previous field campaigns, a 

new algorithm has been developed that makes it possible to emulate a radar and derive 

reflectivity profiles from the observed brightness temperatures. We present preliminary results 

from GRIP, including close-up views of the convective structure of Hurricane Karl as it 

intensified to category 3. The Global Hawk flew over Karl for 13 hours and passed over the eye 

20 times during this period, and with HAMSR it is possible to analyze the three-dimensional 

convective structure of the inner core as it evolves. And since HAMSR is a sounder, it is also 

possible to analyze the thermodynamic structure in areas surrounding the core. GRIP was 

operated in coordination with NOAA and the NSF, and observations were collected from 

numerous sensors on multiple aircraft platforms. The analysis of this rich data set is just 

beginning. 

Copyright 2011 California Institute of Technology. Government sponsorship acknowledged. 


NPP Microwave-sounder Based Tropical Cyclone Products 

Andrea Schumacher 1 , Mark DeMaria 2 , John A. Knaff 2 , Limin Zhao 3 , Tom Schott 4 

(schumacher@cira.colostate.edu) 

1 Cooperative Institute for Research in the Atmosphere, Fort Collins, CO; 

2 NOAA/NESDIS/STAR, Fort Collins, CO; 3 NOAA/NESDIS/OSPO/SPSD, Camp Springs, MD; 

4 NOAA/NESDIS/OSD, Suitland, MD 

NESDIS provides several Advanced Microwave Sounding Unit (AMSU)-based operational 

tropical cyclone (TC) intensity and structure guidance products. Using temperature retrievals 

corrected for scattering and attenuation a number of tropical cyclone products are generated. 

These products include storm-centered radius vs. pressure profiles of temperature and gradient 

winds, objective estimates of 1-min maximum sustained surface winds, minimum sea level 

pressure, the radii of 34-, 50-, and 64-kt winds in the northeast, southeast, southwest, and 

northwest quadrants, and balanced horizontal winds on standard pressure levels from 1000 hPa 

to 100 hPa within 600 km of tropical cyclones. Product algorithms use statistical methods to 

remove temperature biases due to scattering and attenuation, and by using NCEP boundary 

conditions and hydrostatic balance heights fields can be estimated. Statistical analysis is then 

used to estimate intensity and wind radii from storm-centered azimuthally averaged fields and 

gradient wind estimates. The 2-dimensional winds are estimated on standard pressure levels by 

solving the non-linear balance equations. 

With the launch of the National Polar-Orbiting Operational Environmental Satellite System 

(NPOESS) Preparatory Project (NPP) satellite, data from a new microwave sensor, the Advanced 

Technology Microwave Sounder (ATMS) which has ~35% smaller footprint than AMSU, will 

be available. This presentation will discuss the procedure and timeline for updating the AMSUbased 

TC intensity and structure products to use ATMS data and the potential product quality 

improvements that may result from the updates. 

DISCLAIMER: The views, opinions, and findings in this report are those of the authors and 

should not be construed as an official NOAA and/or U.S. Government position, policy, or 

decision 


The 2010 GOES-R Proving Ground at the National Hurricane Center 

Jack Beven 1 , Michael Brennan 1 , Mark DeMaria 2 , John Knaff 2 , Christopher Velden 3 and Jason 

Dunion 4 

(John.L.Beven@noaa.gov) 

1 NOAA/NWS/NCEP National Hurricane Center, Miami, FL; 2 NOAA/NESDIS/STAR, Fort 

Collins, CO; 3 CIMSS/UW, Madison, WI; 4 University of Miami/CIMAS-NOAA/AOML/HRD, 

Miami, FL 

GOES-R is scheduled for launch in late 2015 and will contain a number of new instruments, 

including the 16-channel Advanced Baseline Imager (ABI) and the Geostationary Lightning 

Mapper (GLM). The GOES-R Proving Ground was established to provide forecasters with 

advance looks at GOES-R data and products using proxy information, and to obtain user 

feedback for the product developers. Six products were chosen for demonstration at NHC during 

most of the 2010 Hurricane Season (1 Aug to 30 Nov). Five of the six were ABI products, which 

included the Hurricane Intensity Estimate (HIE), two Red-Green-Blue (RBG) products designed 

to provide forecasters experience with image combinations, split window (10.8 and 12.0 µm) 

infrared imagery for tracking low to mid-level dry air, and super-rapid scan operations imagery. 

The sixth was a combined GLM and ABI product to predict rapid intensification using global 

model fields, infrared imagery and lightning input. SEVIRI data from Meteosat and the imager 

from the current GOES were used as proxies for the ABI and the ground-based Global Lightning 

Dataset 360 (GLD-360) was used as a proxy for the GLM. Results from 2010 will be 

summarized along with plans for a follow-on experiment during the 2011 Hurricane Season. 



decision. 


Development and validation of a capability for wide-swath storm observations of ocean 

surface wind speed 

Timothy L. Miller 1 M. W. James 1 , W. L. Jones 2 , C. S. Ruf 3 , E. W. Uhlhorn 4 , C. D. Buckley 5 , S. 

Biswas 2 , G. Shah 2 , and R. E. Hood 6 

(tim.miller@nasa.gov) 

1 NASA Marshall Space Flight Center, Huntsville, AL; 2 University of Central Florida; 

3 University of Michigan; 4 NOAA/AOML/HRD; 5 Universities Space Research Association; 

6 NOAA/UAS Program 

HIRAD (Hurricane Imaging Radiometer) flew on the WB-57 during NASA’s GRIP (Genesis 

and Rapid Intensification Processes) campaign in September of 2010. HIRAD is a new C-band 

radiometer using a synthetic thinned array radiometer (STAR) technology to obtain cross-track 

resolution of approximately 3 degrees, out to approximately 60 degrees to each side of nadir. By 

obtaining measurements of emissions at 4, 5, 6, and 6.6 GHz, observations of ocean surface wind 

speed and rain rate can be inferred. This technique has been used for many years by precursor 

instruments, including the Stepped Frequency Microwave Radiometer (SFMR), which has been 

flying on the NOAA and USAF hurricane reconnaissance aircraft for several years. The 

advantage of HIRAD over SFMR is that HIRAD can observe a +/- 60-degree swath, rather than 

a single footprint at nadir angle. 

Results from the flights during the GRIP campaign will be shown, including comparison with 

SFMR of preliminary images of brightness temperatures, and possibly wind speed and rain rate. 

If available, comparisons will be made with observations from other instruments on the GRIP 

campaign, for which HIRAD observations are either directly comparable or are complementary. 

Potential impacts on operational ocean surface wind analyses and on numerical weather forecasts 

will also be discussed. 


Developments in 2010 in in-flight real-time reporting of the directional ocean wave spectra 

using Wide Swath Radar Altimeter (WSRA) from the NOAA WP-3D Hurricane 

Reconnaissance Aircraft 

Ivan PopStefanija 1 , Edward J. Walsh 2 

(popstefanija@prosensing.com) 

1 ProSensing, Amherst, MA; 2 NOAA/ESRL/PSD, Boulder, CO 

This JHT project focuses on developing the processing algorithms and real-time software needed 

to perform in-flight data processing for the newly-developed Wide Swath Radar Altimeter 

(WSRA). The WSRA is a novel digital beamforming radar altimeter developed with funding 

from the NOAA SBIR program, with additional support from the University of Massachusetts 

and DARPA. 

In March of 2010, we had a partially-successful test flight. It was only a partial success because 

the WSRA's power amplifier worked only intermittently during the flight. The WSRA hardware 

was fixed by June 2010. Throughout the summer of 2010, ProSensing engineers worked on the 

implementation of the real-time processing code for the unattended operation of the WSRA 

system. This effort included optimization of the WSRA digital beamforming and range centroid 

tracking algorithms, conversion of the processing algorithms into a multi-threaded C application, 

and deployment of a multi-core PC processor to execute in-flight processing. In the new code we 

also implemented several WSRA algorithm improvements: (1) antenna beam pointing angle 

adjustment factor calculated based on the estimation of the antenna array width distortion caused 

by the lateral movement of the aircraft during the data integration time (2) incremental (looped) 

estimation of the range-to-surface in each beam weighed by the range estimates in the 

neighbouring beams, (3) automatic adjustment of the WSRA radar parameters as the auxiliaryreported 

aircraft’s altitude changes, (4) streamlining and automating the backend processing 

which estimates the ocean wave directional spectra from the surface elevations, and (5) 

developing the script that would format the data products and transmit in-flight the WSRA 

output data file from the aircraft to the archiving and displaying computers at AOC in Tampa and 

NHC in Miami. Upon completion of the software development, the WSRA was shipped to AOC 

for the installation on WP-3D. 

The WSRA was installed on the WP-3D aircraft mid-September, thereby missing the opportunity 

to fly on several reconnaissance flights in hurricane Earl. For the rest of the season the WSRA 

operated during one flight into a tropical disturbance south of Haiti and one reconnaissance flight 

into CAT-1 hurricane Karl. The second half of the hurricane season did not provide any 

additional opportunities to operate WSRA. All parts of the WSRA software were successfully 

tested, including the transmitting of the data to AOC. Software and hardware performance during 

flights have shown the feasibility of a fully-automated unattended operational WSRA. The two 

flights we’ve conducted illuminated some problems in the WSRA code which have been since 

corrected and tested. Currently, the WSRA is at AOC ready for operation during the 2011 

hurricane season. 


NOAA Proof of Concept Demonstrations of Hurricane Observing Strategies using 

Unmanned Aircraft Systems 

Robbie Hood 1 , Robert Atlas 2 , Frank Marks 2 , Steve Koch 4 , Robert Rogers 2 , Joseph Cione 2 , 

Michael Black 2 , Eric Uhlhorn 2 , Christopher Landsea 3 , Gary Wick, Yuanfu Xie 4 , Phil Hall 5 , 

Nancy Ash 5 , and Phil Eastman 5 

(robbie.hood@noaa.gov) 

1 NOAA/OAR/UASP; 2 NOAA/ Atlantic Oceanographic and Meteorological Laboratory; 

3 NOAA / National Hurricane Center; 4 NOAA / Earth System Research Laboratory; 5 NOAA/ 

Office of Marine and Aviation Operations 

The NOAA Unmanned Aircraft Systems (UAS) Program is evaluating the feasibility of UAS 

technologies to address the NOAA mission using a requirements-based systems approach. UAS 

have the potential to fill critical observation gaps in understanding and predicting high impact 

weather events impacting coastal communities. The NOAA UAS Program has been identifying 

and conducting conceptual studies of UAS platforms and payloads which could be beneficial for 

long endurance sampling of tropical cyclone boundary layers and remote sensing of storm 

structures. The NOAA UAS Program is also investing in Observing System Simulation 

Experiments (OSSE) to analyze whether positive impact to future tropical cyclone observing 

strategies could be achieved with UAS observations. This presentation will include an overview 

of the NOAA UAS Program High Impact Weather Roadmap for testing and evaluating UAS 

technologies. Recent accomplishments and key partnerships with NASA, NSF, and academic 

community will also be discussed. 


Surface-Reflected GPS Wind Speed Sensing Results for 2010 Atlantic Season 

Michael S. Grant 1 , Stephen J. Katzberg 2 , Jason P. Dunion 3 

(michael.s.grant@nasa.gov) 

1 NASA/Langley Research Center, 2 NASA/Distinguished Research Associate, 3 University of 

Miami/RSMAS/CIMAS-NOAA/AOML/HRD 

During the 2010 Atlantic storm season, NASA-Langley GPS receiver/reflectometers deployed 

on NOAA P-3 Hurricane Hunter aircraft were used to retrieve ocean surface wind speed for a 

number of storms including Hurricane Earl, Tropical Storm Alex, and for a rapid intensification 

flight into Hurricane Karl. The sensing technique uses surface-reflected GPS navigation signals 

in a manner analogous to bistatic radar, where Global Positioning System (GPS) satellites serve 

as surface illumination sources. A modified GPS receiver measures surface-reflected signal 

strength at increasing path delays, relative to the geometric mirror reflection point. Surface wind 

speed is inferred by monitoring ocean surface roughness (mean square slope) via the measured 

scattering of the reflected signal. 

Results from earlier storm seasons verified the reflected signal sensitivity over a range of wind 

speeds: from nearly 0 (calm seas) to greater than 40 meters per second (m/s) [1]. Another study 

reported that, for 0 – 15 m/s wind conditions and well-developed seas, GPS wind speed retrievals 

were in agreement with TOPEX satellite altimeter-derived measurements to better than 1 m/s, 

with a precision ~2 m/s (1-sigma) [2]. Surface wind speeds obtained using an empirical 

calibration function also compared well to GPS dropsonde data, particularly for winds in the 0 – 

20 m/s range [3]. In this paper, GPS reflection measurement results from the 2010 storm season 

will be presented and compared to co-located measurements from the operational Stepped- 

Frequency Microwave Radiometer, surface-adjusted flight level winds, and GPS dropsondes. 

The GPS reflection measurements were achieved using light-weight (< 5 kg), low power, 

autonomously operated GPS receivers and nadir-viewing 3.5” hemispherical antennas – a system 

which requires only minimal aircraft accommodation. GPS wind speed instruments deployed on 

longer-duration aircraft missions could be useful for mapping the changing surface wind field 

and changes in momentum flux related to the ultimate intensity and classification of developing 

storm systems. 

The sensitivity of the GPS instrument to low-speed surface wind conditions (< 10 - 15 m/s), 

where microwave radiometers can be less effective, implies that GPS surface-reflection 

instruments can provide independent wind speed retrievals to compliment those obtained with 

radiometers or other instruments currently utilized in tropical cyclone genesis and forecasting 

studies. Combining wind speeds based upon GPS surface reflections (due to larger surface 

slopes) with those derived from radiometric brightness temperature (involving finer surface 

features) can potentially provide a more complete understanding of tropical cyclone formation, 

and improve forecasts of storm intensity. 

[1] Katzberg, S. J., O. Torres, and G. Ganoe (2006), ‘Calibration of reflected GPS for tropical 

storm wind speed retrievals,’ Geophys. Res. Lett., 33, L18602, doi:10.1029/2006GL026825 

[2] Garrison, J. L., et. al., (2002) ‘Wind speed measurements using forward scattered GPS 

signals,’ IEEE Trans. Geoscience and Remote Sensing, vol. 40, no. 1. 

[3] Katzberg, S. J., and J. Dunion (2009) ‘Comparison of refl. GPS wind speed retrievals with 

dropsondes in tropical cyclones,’ Geophys. Res. Lett., 36, L17602, doi: 10.1029/2009GL039512. 


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Session 4 

Observations and 

Observing Strategies for 

Tropical Cyclones and 

their Environment, Part 2 

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Real-Time Airborne Ocean Measurements and Predictions of Loop Current Eddy 

Shedding During the Deepwater Horizon Oil Spill: Implications for Hurricane Intensity 

Forecasting 

Lynn K. Shay 1 , Benjamin Jaimes 1 , Jodi K. Brewster 1 , Patrick Meyers 1 , Claire McCaskill 1 , 

Steven Paul 2 , Eric W. Uhlhorn 3 , Frank D. Marks 3 , George R. Halliwell Jr. 4 

(nshay@rsmas.miami.edu) 

1 Division of Meteorology and Physical Oceanography, RSMAS, University of Miami; 2 Office of 

Aircraft Operations, NOAA, MacDill AFB 3 Hurricane Research Division, NOAA, AOML 

4 Physical Oceanography Division, NOAA, AOML 

Several flights from NOAA WP-3D aircraft were conducted between 5 May and 9 July 2010 that 

focused on temperature, currents and salinity in a geographical location to the southeast of the 

Deepwater Horizon (DWH) rig, and over the Loop Current (LC) and associated eddies. These 

flights provided the evolving oceanic variability of the LC, the shedding of warm core eddy 

Franklin, and frontal eddies along its' periphery. Atmospheric dropsondes (for surface winds) 

and airborne expendable ocean profilers sampling to as deep as 1500 m (from expendable current 

profilers: AXCP) were deployed in a lawnmower pattern with essentially the drop points. Over 

700 airborne ocean profilers were deployed that included AXBT, AXCP, and conductivitytemperature-depth 

profilers (AXCTD). These data, acquired over a weekly basis over the LC, 

were assimilated into operational ocean models (HYCOM) at NAVOCEANO to predict potential 

pathways of the oil from the northern Gulf of Mexico. In addition, these measurements provided 

data to vector ships to regions of mesoscale variability for detailed oil spill measurements, and 

are being used to evaluate satellite-based products such as oceanic heat content from altimetry 

and SMARTS climatology. 

Surface currents derived from altimeter sea surface heights and direct current measurements 

from AXCPs indicate that, from May to June, the circulation patterns between the DWH rig and 

the northern boundary of the LC were dominated by nearly small-scale cyclones. Eddy Franklin 

detached from the LC between 28 May and 18 June, where the 20 o C isotherm depth (h20) 

reached maximum values of about 320 m at Franklin’s core, compared with values ranging from 

280 to 300 m before the shedding event. During early July, Franklin experienced significant 

erosion from several frontal eddies, where h20 values in Franklin’s core ranged from 260 to 280 

m. Subsequently, Franklin began to move westward as expected with large warm core eddies. 

Thus, the approach captured the complexities of the mesoscale LC-eddy shedding processes for 

the first time over weekly time scales. The thermal structure data from all profilers were 

assimilated into the operational HYCOM whereas the salinity and current data are being used to 

evaluate model performance. Analyses of twin numerical experiments with and without data 

assimilation clearly revealed the unprecedented importance of the real-time, 3-D measurements 

in improving the trajectories to guide cleanup efforts. This approach needs to be applied to 

oceanic and coupled model efforts and implemented for real-time ocean forecasting at the 

National Centers for eventual use in coupled model forecasts. 


First Flights of HIWRAP During GRIP 

Gerald Heymsfield 1 , L. Li 1 , J. Carswell 2 , M. Mclinden 1 , M. Perrine 1 , L. Tian 3 , A. Reynolds 1 , S. 

Guimond 4 

(gerald.heymsfield@nasa.gov) 

1 NASA Goddard Space Flight Center; 2 Remote Sensing Solutions; 3 UMBC GEST; 4 NASA 

ORAU 

Wind measurements are crucial for understanding and forecasting tropical storms since 

they are closely tied to the overall dynamics of the storm. The High-Altitude Imaging Wind and 

Rain Airborne Profiler (HIWRAP) is a dual-frequency (Ka- and Ku-band), dual-beam (30 0 and 

40 0 incidence angle), conical scan, solid-state transmitter-based system, designed for operation 

on the high-altitude (20 km) Global Hawk UAV. HIWRAP images the winds through volume 

backscattering from clouds and precipitation, enabling it to measure the tropospheric winds 

above heavy rain at high levels. It will also measure ocean surface winds through scatterometry, 

similar to QuikScat. These measurements from higher altitudes above storms, are useful for 

providing higher spatial and temporal resolution than obtained by current satellites and loweraltitude 

instrumented aircraft. 

HIWRAP flew its first test flights during March 2010 on the NASA WB-57 manned 

aircraft (60-65kft ceiling) and then the first science flights on the unmanned Global Hawk (65kft 

ceiling) during the Genesis and Rapid Intensification Processes (GRIP) campaign conducted 

during August and September 2010. The Global Hawk flew for the first time over hurricanes 

during GRIP. The were 5 science flights over storms (Hurricanes Karl, Earl, and Matthew) 

during which there were as many as 20 passes over the storm center during a single flight. 

HIWRAP data analysis from these flights is in very early stages of processing and software 

development. We will present a summary of the instrument status, data analysis, lessons learned, 

and future plans. 


WISDOM Intensity Program – Weather Hurricane In-situ Sea Surface Probe (WHISSP) 

Justyna Nicinska, Russell B. Chadwick, Randy Johnson, 

(justyna.nicinska@noaa.gov) 

Office of Oceanic and Atmospheric Research (OAR)/NOAA 

The WISDOM Intensity program is a new research effort based in the Office of Oceanic and 

Atmospheric Research (OAR) with the aim of developing observing platforms capable of 

delivering continuous data within the eye of a tropical cyclone. At present data collection in the 

eye of a hurricane is limited. The WISDOM effort was inspired by the successful Aeroclipper 

design led by CNES in which two models were entrained into a tropical cyclone in the Indian 

Ocean and collected data for over a week. OAR/WISDOM aims to develop a low cost platform 

capable of collecting continuous observations for days in the eye of a hurricane including central 

pressure, wind speed, wind direction and air temperature. One of several possible approaches 

towards developing a simple and low-cost version of a platform for collecting data in the eye of a 

storm is the Weather/Hurricane In-situ Sea Surface Probe (WHISSP). This presentation will 

describe the simple wind model developed to assess a surface craft’s ability to become entrained 

in a tropical cyclone as well as results from an initial proof of concept study conducted by 

OAR/WISDOM, where four experimental WHISSP models were tested in the field. Results of 

this study as well as future development plans will be discussed. 


New Tools for Tropical Cyclone Radar Rainfall Estimation 

Dan Berkowitz 

(Daniel.S.Berkowitz@noaa.gov) 

Radar Operations Center, Norman, OK 

During the early years of the WSR-88D program, an empirical relationship, known as the default 

Z/R relationship, was used to convert radar reflectivity to a rainfall rate. However, it was known 

to underestimate rainfall in tropical-like systems. In June 1997, a tropical Z/R relationship was 

authorized by the Radar Operations Center (ROC) which yielded higher rainfall rates than the 

default relationship for tropical systems. However, the performance of the tropical Z/R 

relationship remained inconsistent. Part of the problem was that one Z/R relationship was applied 

to the entire 230 kilometer range within which rainfall estimates were computed even though 

different types of rain regimes are possible within a tropical cyclone (TC). Additionally, once the 

tropical Z/R relationship was selected, it was used until an operator changed it. These challenges 

highlighted the need for an improved method for estimating rainfall amounts. This presentation 

will provide an overview of the traditional (reflectivity-based) method, plus two new rainfall 

estimation tools worth considering for the upcoming tropical cyclone season - the vertical profile 

of reflectivity (VPR)-based method developed by the National Severe Storms Laboratory and the 

new Dual Polarization (DP) Quantitative Precipitation Estimation (QPE) method. 


A Two-Dimensional Velocity Dealiasing Algorithm for the WSR-88D 

W. David Zittel 1 , Zhongqi Jing 1 , Nicholas Langlieb 2 

(Walter.D.Zittel@noaa.gov) 

1 Radar Operations Center, Norman, OK; 2 National Weather Service Forecast Office, Great Falls 

MT 

The current Weather Surveillance Radar-1988 Doppler (WSR-88D) utilizes two velocity dealiasing 

schemes, the Velocity Dealiasing Algorithm (VDA) and the Multiple Pulse Repetition Frequency 

(PRF) Velocity Dealiasing Algorithm (MPDA). The VDA remains virtually unchanged since the 

deployment of the legacy WSR-88Ds. The VDA primarily uses radial continuity, an average of 

nearby velocity neighbors, or an Environmental Wind Table (EWT) to help resolve winds exceeding 

the maximum unambiguous velocity (Nyquist Velocity, V N ) which for the WSR-88D is between 21 

and 35 m s -1 for the following precipitation Volume Coverage Patterns (VCPs): VCPs 11, 12, 21, 211, 

212, & 221 and the clear air VCP 32. The long-pulse clear air VCP 31 has a Nyquist velocity of about 

8 m s -1 . While generally reliable, the VDA can fail: 1) under strong shear conditions; 2) in velocity 

data with moving clutter; 3) in areas with weak echoes; 4) when the Nyquist velocity is much lower 

than the prevailing winds; or 5) where the values in the EWT are not representative of the local storm 

winds. The MPDA, fielded in 2004 as VCP 121, takes multiple scans of velocity data at the same 

elevation using up to three different PRFs. It can dealias velocity with a high degree of reliability 

where there is more than one velocity estimate available. However, the utility of the MPDA in VCP 

121 is limited during rapidly changing weather events because the additional scans required increases 

the volume scan time to nearly 6 minutes. VCP 121’s utility is further diminished because it has only 

9 unique elevation angles with which to interrogate storm structure. 

The Radar Operations Center (ROC) tested a two-dimensional velocity dealiasing scheme (VDEAL) 

that is more robust than the current VDA. It works by simultaneously dealiasing all gates in an 

elevation scan using a least-squares approach to minimize the discontinuity caused by aliasing. 

Greater weight is given to velocity differences near zero or at multiples of 2V N as well as velocity 

differences where the corresponding spectrum width values are low. VDEAL can be used by all VCPs 

except VCP 121 with no perceptible delay in product availability. 

This paper presents the test results of VDEAL on historical WSR-88D data sets collected during 

hurricanes, tornadic storms, and storms with outflow boundaries. For this test, velocity products were 

scored qualitatively. Of 520 low-level velocity products evaluated, the VDA had 252 with dealiasing 

errors while VDEAL had only 71 with dealiasing errors. More striking was the reduction in velocity 

dealiasing errors and improved data quality of the VDEAL over the VDA in hurricanes. Of 201 

velocity products evaluated, VDA had 185 total dealiasing errors while VDEAL had only 5 dealiasing 

errors. Based on these results and independent testing by scientists at the National Severe Storms 

Laboratory, the ROC plans to conduct a field test during the summer and fall of 2011. 


A summary of new activities to expand the Caribbean sounding and surface networks 

The IASCLIP and COCONet initiatives 

Michael W. Douglas 

(Michael.Douglas@noaa.gov) 

National Severe Storms Laboratory/NOAA 

Norman, Oklahoma 

Two very different activities that are now spinning up should substantially improve surface 

measurements and tropospheric profiling across the Caribbean Sea region and neighboring 

regions. The Continuously Operating Caribbean GPS Observational Network (COCONet), 

funded by NSF, will install approximately 50 new GPS stations that, although intended primarily 

to measure tectonic motions for geophysical research, will also have co-located automatic 

weather stations reporting in real time. The COCONet observations will provide nearly 

continuous estimates of precipitable water much like the current Suominet sites. These estimates 

can be used both for real-time analysis and model initialization and for comparison with, and 

calibration of, routine radiosonde moisture information. More information on COCONet can be 

found at: 

http://www.unavco.org/community/meetings-events/2011/coconet/agenda.html 

Overlapping some of the objectives of COCONet is the Intra-Americas Study of Climate 

Processes (IASCLIP) program, being supported initially by NOAA, which although focused on 

climate variability, also seeks to improve the atmospheric and oceanic monitoring over the 

region on all time scales. Some of the desired improvements to the observing network over the 

Caribbean region overlap those being proposed by COCONet and there will likely be joint 

development of some aspects of the networks. More information on the IASCLIP can be found 

at: 

http://www.eol.ucar.edu/projects/iasclip/ 

This talk will summarize both the COCONet network and the proposed initial IASCLIP 

enhancements over the region. Modification to the current CHUAS (Cooperative Hurricane 

Upper-Air Stations) network to include adaptive observations at additional sites, proposed as part 

of IASCLIP and also to the JHT, will also be described. 


Establishing an Improved National Capability for Collection of Extreme Storm and Flood 

Data 

This abstract was drafted by the members of the Office of Federal Coordinator's Workgroup on 

Disaster Impact Assessments: Weather and Water Data, including William Birkemeier 

(USACE), Dan Catlett (FEMA), William L. Coulbourne ( Wind and Flood Hazard Mitigation 

Applied Technology Conference), Robert R. Holmes (USGS, Robert R. Mason, Jr. (USGS), 

Anthony R. Ramirez (NOAA), Wilson Shaffer (NOAA), and D. Phil Turnipseed (USGS) and 

presented by Robert Mason, Workgroup Chair, on behalf of the committee. 

The National Oceanic and Atmospheric Administration’s (NOAA) National Weather Service 

(NWS) flood forecasting operations saves thousands of lives and reduce injuries and property 

damage by billions of dollars annually. But this process, which depends on data from thousands 

of U.S. Geological Survey streamgages and NOAA meteorological stations, usually does not 

provide data coverage sufficient to adequately document the extensive impacts of a major storm 

or flood or enable understanding of small-scale, localized processes. As a result, network 

observations often are supplemented by post-storm surveys and studies of rainfall, flood marks, 

and wind damage to fill in observational gaps and obtain a more complete spatial coverage. In 

turn, these data are studied by the Federal Emergency Management Agency, the National 

Institute of Science and Technology, and various State agencies resulting in advancements in 

building codes and construction practices. 

Today, post-storm surveys and traditional networks can be greatly augmented by pre-event 

deployment of small, self-contained instruments in spatially dense, temporary networks to 

monitor the event directly and continuously. Clusters of self-logging pressure transducers and 

real-time rapid-deployment gages monitor waves and water-levels and anemometers and truckmounted 

Doppler radars monitor wind speed and direction at rapid intervals. These data 

describe the evolution of storms and floods with unprecedented spatial and temporal detail, 

particularly floods of coastal waters and wetlands. The resulting data can be used to (1) develop 

more accurate and robust wind, storm-surge, and flood models; (2) derive better structure design 

criteria and building codes; and (3) improve warning systems. 

Effective utilization of these mobile networks requires the timely and well-coordinated efforts to 

deploy equipment into targeted areas in anticipation of the storm. In response to this need, 

various Federal agencies and affiliated organizations have created the National Plan for Disaster 

Impact Assessments: Weather and Water Data (NPDIA), which establishes a procedural template 

for coordinating various pre-storm readiness activities and post-storm responses. The plan is 

available from the publications web page of Office of the Federal Coordinator for 

Meteorological Services and Supporting Research (OFCM) at URL: 

http://www.ofcm.gov/homepage/text/pubs.htm. 

This presentation will describe procedures for coordinating deployment activities, capabilities of 

the participating agencies and affiliated organizations; mechanisms for aggregating and sharing 

resources; plans for documenting the event; and links to acquired data. By working together and 

with other stakeholders we can better collect the timely and useful data needed to develop more 

robust and resilient communities and a safer, disaster resilient Nation. 


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Session 5 

Tropical Cyclone Model 

Development and 

Technology Transfer, 

Part 1 

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Advancements to the Operational HWRF Modeling System at EMC 

Vijay Tallapragada 

(vijay.tallapragada@noaa.gov) 

NOAA/NWS/NCEP/EMC/HWRF 

The National Centers for Environmental Prediction (NCEP)/Environmental Modeling Center 

(EMC) operational Hurricane Weather Research and Forecast (HWRF) modeling system has 

been upgraded for implementation in 2011 hurricane season. Through a collaborative effort, 

EMC and the Developmental Testbed Center (DTC) have upgraded the non-hydrostatic 

mesoscale model (NMM) core of the HWRF system from V2.0 and synchronized it with the 

latest version of WRF NMM V3.2+, allowing the operational and research communities to share 

the same code base and help accelerate further advancements to the HWRF modeling system 

through an efficient Research to Operations (R2O) infrastructure. Developmental activities for 

the HWRF system for 2011 hurricane season also included improvements to the vortex 

initialization procedure, new GFS deep convection parameterization, improved surface physics 

formulation, expanded Princeton Ocean Model (POM) Eastern Atlantic domain and enhanced 

hurricane model diagnostics designed to identify areas for improvement. 

The coupled HWRF system was uniquely designed to make significant advancements in 

improving operational forecast skill of intensity and structure forecasts in addition to advancing 

wave and storm surge forecasts to address the coastal inundation problem. Continued 

advancements in track prediction will remain an important focus of this prediction system. 

Further improvements to the HWRF modeling system is being made possible through the 

support provided by the Hurricane Forecast Improvement Project (HFIP). Accelerating 

advancements in hurricane prediction will require an infusion of resources directed at 

concentrating vital modeling efforts at NCEP in the areas of model resolution, advanced triple 

nested grids, improved air-sea-wave-land coupling, advanced hurricane physics suitable for 

higher resolutions, improved data assimilation methods to ingest new and existing datasets in the 

hurricane core, and high resolution HWRF ensembles to account for uncertainties in the initial 

state and physics. 


Issues in transitioning HWRF upgrades into operations at EMC 

A Joint Hurricane Testbed (JHT) Program 

Robert E. Tuleya, Young Kwon, Vijay Tallapragada, 

Zhan Zhang, Yihua Wu, Qingfu Liu, and J. O’Connor 

(Robert.tuleya@noaa.gov) 

CCPO/ODU 

The 2010-2011 JHT project funded through the Center for Coastal Physical Oceanography (CCPO) 

at Old Dominion University (ODU) has concentrated on HWRF development, its operational 

implementation, and recent upgrades. Over the last year emphasis on this project has been on trouble 

shooting problems involving model biases of intensity and issues involving land interaction. The 

long-standing HWRF problem with unrealistic, cold land surface temperatures was corrected with 

the 2010 forecast system. Some further analysis and possible refinements to these land-related issues 

will be discussed in addition to refinements in the new HWRF surface flux package. 

A new surface flux package based on observations was implemented for the 2010 season that has in 

part contributed to some improvements of track and intensity in HWRF. This new 2010 surface flux 

package has been further examined and contrasted with packages used in other operational models. 

Furthermore, this new package was generalized and recast in terms of momentum and thermal 

roughness lengths. This new revised code has been installed in the new HWRF V3 model version to 

be installed for 2011 operations. Some comparisons will be shown in running the HWRF model 

using different flavors of the new formulation. 

In order to quantify the impact of using a more sophisticated land model, i.e. the NOAH LSM, 

HWRF underwent extensive testing in 2010. These tests including running the operational system, 

H210, both for numerous historical cases of 2008-2009 and for nearly 300 cases in real-time for the 

2010 Atlantic season. Besides using the NOAH LSM surface option, the tests also included changes 

to the operational system to allow more frequent output of surface and sub-surface runnoff - a 

requiremnt for a stream routing model. The standard verification parameters of mean track and 

intenity errors were applied to these suite of cases. As opposed to prelimiary results using a previous 

HWRF model version, the 20120 HWRF version with the NOAH LSM option led to some 

degradation in both track and intensity at some forecast times. These results will be shown. Further 

issues with the proposed 2011 HWRF version involving the transition from WRF 2 to WRF3 will 

also be shown. 


2011 operational HWRF model upgrades 

Young Kwon, Vijay Tallaparagada, Robert Tuleya, Qingfu Liu, Kevin Yeh, Zhan Zhang, Sam 

Trahan and Janna O’Connor 

(Young.Kwon@noaa.gov) 

EMC/NCEP/NWS/NOAA 

The hurricane model team at EMC/NCEP is working on upgrade of the operational HWRF 

model for the year 2011 hurricane season. There are three main components of the upgrades, 

which are 1) modified vortex initialization method, 2) new deep convection parameterization 

with revised surface physics and 3) bug fixed of microphysics and radiation in addition to 

dynamic core upgrade to NMM v3.2. 

The preliminary results indicate that the initialization and physics upgrades improve the 

accuracy of intensity and track forecast of HWRF model respectively while the bug fixes do not 

impact the skill of the model significantly. Especially, the new initialization scheme significantly 

improve the intensity forecast skill of 0-48 hour forecast ranges with maximum about 25% 

compare to the old method. The test cases, detailed explanations of upgrades will be presented 

during the conference. 


Major Upgrades Planned in 2011 for the GFDL Hurricane Prediction System 

Morris A. Bender 1 , Isaac Ginis 2 , Biju Thomas 2 , and Richard Yablonsky 2 

(Morris.Bender@noaa.gov) 

1 DOC/NOAA/Geophysical Fluid Dynamics Laboratory; 2 Graduate School of Oceanography, 

University of Rhode Island 

Major upgrades to the GFDL hurricane prediction system, run operationally by the 

National Weather Service, have been extensively tested and evaluated for operational 

implementation in 2011. These changes include upgrade of the deep convection scheme to the 

version implemented into NCEP’s Global Forecast System (GFS) in 2010, implementation of the 

new GFS shallow convection, modification of the enthalpy exchange coefficient (Ch), inclusion 

of solar radiation into the ocean coupler, several bug fixes in the surface physics and ocean 

coupling code, extension of the eastern Atlantic ocean domain, and adoption of a more 

consistent dissipative heating scheme. 

Preliminary results, using initial and boundary conditions taken from the new GFS 

planned for operational implementation in 2011, show about a 20% decrease in track error in the 

4-5 day range, for 305 forecasts run for storms during the 2010 Atlantic hurricane season. This 

improvement was statistically significant at the 95% level. Reduction of track error was even 

more pronounced for major hurricanes Danielle, Earl and Igor, with over a 22% reduction in 

track error in the 2-5 day forecast time period. 

Evaluation of the environment fields indicate that with the new physics package, the 

forecast evolution of the sub-tropical high was much better simulated over the central and 

western Atlantic. This resulted in a marked reduction in the model’s bias for premature 

recurvature, particularly for intense hurricanes. 

Examples of some of the storm tracks will be shown for select cases, as well as examples 

of differences in the environmental fields forecasted by the upgraded model compared to the 

current operational system. Since upgrades are also planned for the GFS before the start of the 

2011 hurricane season, results will also be shown, on the impact of these changes for both the 

GFS and GFDL performance. Overall impact on intensity so far has been mostly neutral with the 

new model. 

Funding for this work has been provided by the NOAA Joint Hurricane Testbed Program. 


An Overview of COAMPS-TC Development and Real-Time Tests 

James D. Doyle, R. Hodur, S. Chen, J. Cummings, E. Hendricks, T. Holt, H. Jin, Y. Jin, C.-S. 

Liou, J. Moskaitis, M. Peng, K. Sashegyi, J. Schmidt, S. Wang 

(James.Doyle@nrlmry.navy.mil) 

Naval Research Laboratory 

The newly developed Coupled Ocean/Atmosphere Mesoscale Prediction System – Tropical 

Cyclone (COAMPS ® -TC), designed to predict tropical cyclone track, structure, and intensity, has 

been applied in real-time in support of the recent Hurricane Forecast Improvement Project 

(HFIP). These real time forecasts were performed in the Atlantic basin; and in the Eastern, 

Central, and Western Pacific basins during the 2009 and 2010 seasons. Additionally, 

retrospective tests for HFIP were conducted on a large sample of storms (more than 400 cases) 

over the W. Atlantic and E. Pacific basins for hurricanes that occurred in the 2008 and 2009 

seasons. For these real time and retrospective tests, the COAMPS-TC system was configured 

with three nested grids, with 45, 15, 5 km horizontal grid spacings. The inner two meshes 

automatically moved with the tropical cyclone center. 

A number of improvements were made to the COAMPS-TC physics and data assimilation based 

on the results of the 2009 tropical cyclone forecast season. This version of COAMPS-TC was 

then evaluated using the HFIP retrospective cases performed for 2008 and 2009. The intensity 

forecasts for the retrospective tests show the model skill for intensity was superior to other 

dynamical models, particularly for the 30-72 h forecast range. Similarly, an analysis of the 2010 

real-time forecasts in support of HFIP reveals that the COAMPS-TC intensity forecasts for the 

W. Atlantic were superior to other dynamical models for the 30-66 h forecast range. Statistical 

verification from these retrospective tests indicates that the COAMPS-TC system provided 

skillful track forecasts competitive with other limited area models such as the Navy’s GFDN. 

Following the analysis of the 2010 real time forecast results, a number of improvements were 

made to COAMPS-TC including a new algorithm for synthetic observations, inclusion of 

additional observations such as satellite derived total precipitable water that are used by the Navy 

Atmospheric Variational Data Assimilation System (NAVDAS), and a new formulation of 

vertical mixing within clouds and deep convection. Sensitivity test results from this new 

improved version of COAMPS-TC will be presented. Additionally, real-time application of 

COAMPS-TC in the W. Pacific basin during the Interaction of Typhoons and Ocean Processes 

(ITOP) will be discussed. 


Progress towards developing a coupled atmosphere-wave-ocean framework for research 

and operational hurricane models 

Isaac Ginis 1 , Biju Thomas 1 , Richard Yablonsky 1 , Tetsu Hara 1 , Jian-Wen Bao 2 , Chris Fairall 2 , and 

Laura Bianco 2 

(iginis@gso.uri.edu) 

1 Graduate School of Oceanography, University of Rhode Island; 2 NOAA/ESRL/PSD 

We will discuss our progress towards developing a coupled hurricane-wave-ocean framework for 

operational implementation at NOAA and the U.S. Navy. Our goals are to understand the 

physical processes that control air-sea interaction and to develop a physically based and 

computationally efficient coupling at the air-sea interface for use in research and operational 

hurricane models. The key element of the our approach is an air-sea interface module consisting 

of a wave boundary layer model and an air-sea heat and momentum flux budget model that 

explicitly resolve wind-wave-current interaction processes and sea spray effects. So far, the 

module has been imbedded into the experimental version of the GFDL hurricane-wave-ocean 

coupled model and calculates all of the flux boundary conditions for the atmospheric, wave, and 

ocean model components. This module will be implemented into the HWRF coupled system 

later this year. We will present the results of idealized and real-case simulations and evaluate the 

impact of explicit wind-wave-ocean coupling on hurricane track and intensity forecasts. 


Evaluation and Improvement of Ocean Model Parameterizations for NCEP Operations 

Lynn K. Shay 1 , George. R. Halliwell, Jr. 2 , Benjamin Jaimes 1 

(nshay@rsmas.miami.edu) 

1 Division of Meteorology and Physical Oceanography, RSMAS, University of Miami 

2 NOAA/AOML/POD 

The research focused on testing model initialization schemes primarily in the Gulf of Mexico 

(GOM) and processing data required for model evaluation. This dataset includes in situ Naval 

Research Laboratory Acoustic Doppler Current Profiler (ADCP) data from Ivan and during 

Katrina and Rita (courtesy of Minerals Management Service) as well as measurements acquired 

during NOAA Hurricane Research Division Intensity Fluctuation Experiments (IFEX) in pre and 

post Rita in 2005, and during Gustav and Ike (2008). All of these hurricanes have been shown to 

have been affected by warm and cold ocean features in the GOM. Numerical experiments for the 

Ivan case demonstrated the import of model sensitivity to vertical resolution, horizontal 

resolution, vertical mixing, air-sea flux parameterizations (drag coefficients), ocean dynamics, 

and the accuracy of the ocean initialization. 

Analyses of the ocean response to hurricanes Katrina and Rita from in-situ (moorings, airborne 

profilers) and satellite-based measurements have shown significant modulation of the oceanic 

mixed layer cooling by the geostrophically balanced currents in both warm and cold eddies. 

Using an idealized, isopycnic ocean model and wind fields derived from data acquired during 

hurricane Katrina, aspects of the ocean response to tropical cyclones (TC) are investigated in the 

eddies. It is found that rather than a function of the wind stress curl, the upwelling response is a 

function of the curl of wind-driven acceleration of oceanic mixed layer (OML) geostrophic 

currents: upwelling (downwelling) regimes prevail under the TC’s eye over cyclonic 

(anticyclonic) eddies. Predominant isotherm downwelling, wind erosion over deep, warm, and 

nearly homogeneous water columns, and dispersion of OML near-inertial energy only produce 

OML cooling of ~1 o C in anticyclones, consistent with observations. By contrast, widespread 

upwelling of the isotherms and wind-induced mixing over shallow OMLs with enhanced vertical 

current shears produce OML cooling of ~4 o C in cyclones. For oceanic models to correctly 

reproduce TC-induced OML cooling and feedback mechanisms to TC intensity, they must 

accurately resolve mesoscale oceanic features, including position and thermal, density, and 

velocity structures. 

For this reason, ocean model improvement efforts at the National Centers must focus on 

improving the model initialization through assimilation methods. During the summer of 2010, 

an extensive data set was acquired in response to the Deep Water Horizon oil spill in the Gulf of 

Mexico. The 3-dimensional snapshots from NOAA research aircraft of the upper ocean structure 

captured the complex detachment/reattachment processes associated with Eddy Franklin from 

the Loop Current. 


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Session 6 




Part 2 

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Prediction of Consensus TC Track Forecast Error (2005-2010) 

James S. Goerss 

(jim.goerss@nrlmry.navy.mil) 

Marine Meteorology Division, Naval Research Laboratory 

Funded by a JHT project, a graphical predicted consensus error product (GPCE; Goerss 2007) 

was first developed and installed on the ATCF at both NHC and JTWC in 2004. Using GPCE’s 

pool of predictors, revised regression models to be used for the upcoming season were derived 

and installed on the ATCF at both centers from 2005 to 2010. These regression models are used 

to determine the radii of circular areas drawn around the consensus model forecast positions 

within which the verifying TC position is expected to be contained approximately 70% of the 

time. These circular areas are then graphically displayed on the ATCF for use by the forecasters 

at NHC and JTWC. For each season from 2005 to 2010, GPCE is validated for the Atlantic and 

Eastern North Pacific basins. For each forecast length, the GPCE validation percentage is 

compared with the consensus forecast error for the season. As one would expect, since the 

GPCE regression models are derived using the results from previous seasons (e.g., for 2010 the 

dependent data for the Atlantic basin came from the 2003-2009 seasons), the GPCE validation 

percentages for a given season are larger/smaller than the 70% target when the consensus 

forecast errors for that season are smaller/larger than average. For the entire period from 2005 to 

2010, the GPCE validation percentages for the Atlantic basin were 75%, 76%, 76%, 79%, and 

79% for 24h, 48h, 72h, 96h, and 120h, respectively. The respective errors for the eastern North 

Pacific basin were 71%, 73%, 79%, 80%, and 82%. All of the GPCE validation percentages are 

larger than the target for the entire period. This result is consistent with the general reduction in 

consensus forecast error from 2005 to 2010 due to improvements in individual track forecast 

models and the addition of more “good” models (e.g., ECMWF and HWRF) to the consensus. 


Ensemble Forecasting Products for Tropical Cyclones at the UK Met Office. 

Piers Buchanan and Ken Mylne 

(piers.buchanan@metoffice.gov.uk) 

Met Office, Exeter, United Kingdom 

The Met Office global ensemble forecasting model, MOGREPS-15 runs twice a day producing 

global forecasts at 60km resolution out to a 15 day lead time. There is 1 control member and 23 

perturbed ensemble members. Since October 2006, tropical cyclone products have been 

produced twice daily. There are products for individual tracks and strike probability for named 

storms. There are also products generated for 6 worldwide basin areas which track both existing 

storms and potential developing storms. A subset of these products is currently disseminated to 

several international forecasting organisations including the National Hurricane Center. These 

products will be overviewed together with some specific examples of their use. 

Additionally, as part of the TIGGE cyclone exchange project, Met Office ensemble storm 

forecast tracks are shared with those of other forecasting organisations. Some objective 

verification results for combining ECMWF and MOGREPS data will be presented. In addition, 

the combined performance of the 2 ensembles is shown for several examples. 


Large ensemble tropical cyclone intensity forecasting 

Kerry Emanuel 1 , Ross Hoffman 2 , Susanna Hopsch 2 , Daniel Gombos 2 , and Thomas Nehrkorn 2 

(emanuel@mit.edu) 

1 Massachusetts Institute of Technology; 2 Atmospheric and Environmental Research, Inc. 

The advent of ensemble prediction of tropical cyclone tracks has led to improvements in 

the quantification of uncertainty in track forecasts. But the severe computational demands for 

tropical cyclone intensity prediction have limited the utility of ensembles for quantification of 

tropical cyclone intensity forecast uncertainty. We here attempt to circumvent this difficulty by 

running large (100-1000 member) ensembles of tropical cyclone forecasts using the Coupled 

Intensity Hurricane Prediction System (CHIPS) bootstrapped from the ECMWF 51-member 

ensemble forecasts. The CHIPS model is phrased in angular momentum coordinates, allowing 

high resolution of the critical eyewall region at the expense of less resolution of the outer regions 

of the storm. Tracks are generated by calculating the ensemble mean and full covariance matrix 

of the ECMWF track velocities and using these to create a large number of tracks whose velocity 

mean and covariances match those of the ECMWF tracks. But with time, this track algorithm 

evolves into a beta-and-advection technique whose driving winds are derived from the ECMWF 

ensemble forecasts. This also allows us to extend the tracks from 5 to 10 days. Once the tracks 

are created, CHIPS is run along each track to forecast intensity. We will present some results 

from the 2010 hurricane season. 


The Performance of a GFDL Hurricane Model Ensemble Forecast System during the 2010 

Atlantic Hurricane Season 

Timothy Marchok and Morris Bender 

(timothy.marchok@noaa.gov) 

NOAA / GFDL 

Since 1995, the GFDL Hurricane Model (GHM) has been run operationally at NCEP. During 

the 2010 hurricane season, an ensemble forecast system was developed for the GHM and was 

run in near-real time as part of the HFIP Project on the NOAA Jet supercomputer. This talk will 

describe the design of the GHM ensemble forecast system and will summarize results from the 

2010 Atlantic Season. In addition, plans for running this system for the 2011 season will be 

discussed. 

The GHM ensemble forecast system developed in 2010 consisted of 11 members, with one 

control forecast and ten perturbed forecasts. All 11 member forecasts used the same triplynested 

configuration as in operations at NCEP, with a horizontal resolution in the innermost grid 

of 1/12 o . 

Most of the modifications that were made to the GHM system to create the perturbed forecasts 

were designed with the intention of having an impact primarily on intensity forecasts. Six of the 

members were created by modifying storm size parameters that are included on the TC vitals 

storm warning message send from NHC. These members based on storm size were created by 

increasing or decreasing the observed storm size parameters by 25%. One member was created 

by using the environmental filtering scheme from a previous version of the GHM, and another 

member was created by not including the vortex asymmetries from previous forecasts as is done 

in operations. Another member was created by setting a minimum threshold on the radius of 

maximum winds that is different than is done in operations, and the final member was created by 

simply running the GFDL forecast system without including a bogussed vortex. 

Evaluations of the GHM ensemble mean intensity forecasts indicated reductions in forecast 

errors from 24h to 96h ranging from 5.4% to 11.6%. These improvements were statistically 

significant from 36h through 96h. Reductions in track errors were found in the first 72h of the 

forecast period, statistical significance from 12h through 48h and a maximum improvement of 

5.6% at 12h. 

Despite these improvements, results indicated that the ensemble was under-dispersive for both 

track and intensity forecasts, and this will be an area of focus in modifying the system for the 

2011 hurricane season. In addition to the current members which focus mainly on perturbations 

to the observed storm size, we will add some members that include modifications to some of the 

physics parameterizations within the model. 


Evaluation and Development of Ensemble Prediction System for the Operational HWRF 

Model 

Zhan Zhang, V. Tallapragada, R. Tuleya, Q. Liu, Y. Kwon, S. Trahan, J. O’Connor, and W. M. 

Lapenta 

(zhan.zhang@noaa.gov) 

NOAA/NCEP/EMC-IMSG, Camp Springs, MD 

Ensemble prediction system (EPS) has been proven to be effective in reducing various 

uncertainties in model initial states and model physics, and therefore improving model forecast 

skills. This talk reviews the undergoing efforts at NCEP/EMC to develop EPS based on the 

operational Hurricane Weather Research and Forecasting (HWRF) model. The study attempts to 

understand the impact of various uncertainties on the model hurricane track and intensity 

forecasts, and to find out the best combination of ensemble perturbations for HWRF EPS. 

The key to a successful hurricane ensemble forecast is to generate a set of ensembles that 

represent the uncertainties in hurricane model prediction system. The important uncertainties that 

need to be taken into account in hurricane EPS include the uncertainties in the hurricane initial 

structures, initial large scale environment flows, model lateral boundary conditions (LBC), and 

model physics. Following ensemble perturbations are evaluated within the operational HWRF 

model framework: 

• Initial hurricane structures: in order to reduce the uncertainties in initial hurricane 

structure, the observed initial radius of maximum wind is perturbed by 

increasing/decreasing 25% of its value in tcvital file; 

• Large scale environment flows and LBC at initial states: data sets from Global Ensemble 

Forecast System (GEFS), which have resolution of T190L28 and includes 21 ensemble 

members, are used to initialize HWRF domain and LBC; 

• Physics-based perturbations: uncertainties due to model physics can be reduced by using 

various physics packages in HWRF. Several model physics packages have been used for 

this purpose. They include two convective schemes: Simplified Arakawa-Schubert 

(SAS), Kain-Fritsch, and two PBL schemes: GFS PBL scheme, MYJ PBL scheme. 

• Combined ensemble perturbations: all above ensemble forecasts are then combined to 

construct one ensemble. 

Forecast experiments of three hurricanes in 2010 season, Earl, Alex, and Celia, are carried out 

for different ensemble configurations. The track and intensity forecasts from each subset of 

ensemble are evaluated and compared. Different combinations of ensembles are examined to 

find out the best results for HWRF EPS. Various probabilistic forecast products resulted from 

EPS, such as track striking probability, ensemble track spread, are also discussed. 


Forecasting Tropical Cyclone Genesis/Development Using an Ensemble of High Resolution 

Deterministic Global Models – Results from the HFIP 2010 Summer Demo 

Mike Fiorino 

(Michael.Fiorino@noaa.gov) 

NOAA/ESRL/Global Systems Division 

Forecasters at the Joint Typhoon Warning Center (JTWC) and the National Hurricane Center 

(NHC) have, over the past several years, used medium (72-120 h)-to-long-range (5-8 d) global 

model forecasts to qualitatively assess the potential for tropical cyclone (TC) formation. The 

general finding is that if the better-performing global models (ECMWF, GFS and UKMO) all 

generate a surface trough, in roughly the same location, with significant 850 mb relative vorticity 

and strong precipitation, then a TC is likely to occur. 

For the 2010 HFIP summer demo, we applied the 'genesis' version of the GFDL TC tracker to 

quantitatively measure the genesis forecasts of six high-resolution global models available to 

JWTC/NHC, namely the NCEP GFS (dx ~30km), FNMOC NOGAPS (dx ~45km), ECMWF IFS 

(dx ~20km), CMC GEM (dx ~60 km), UKMO UM (dx ~30 km) and the ESRL FIM (dx=30km). 

An objective genesis forecast scheme depends critically on the definition of genesis, in both the 

atmosphere and in the models. 

For the HFIP demo, genesis is defined from an operational perspective according to USPACOM 

INST 0539.1 and the NHOP that require JTWC/NHC issue warnings/advisories for all "tropical 

cyclones" (WMO definition) in their AOR. Thus, the first warning/advisory is issued when a 

system reaches tropical depression strength (typically Vmax = 25 kt) and from this genesis point, 

we define a 30-h 'genesis period' so as to give 00/12UTC models three chances to forecast 

genesis. A successful genesis forecast is when a model 'genesis' storm (cyclones that formed 

during the integration and not model tracks of existing TCs) matches an actual TC during the 

genesis period. 

Results from the 2010 northern Hemisphere season are presented by basin (NIO, WPAC, EPAC 

and LANT); the main finding is that for systems that eventually reach hurricane strength, the 

better TC forecast models (ECMWF and GFS) successfully forecast genesis at day 5 about 65% 

of the time. We also use the genesis forecasts to diagnose spurious model storms or 'spuricanes' 

and how these false alarms depend on the model convective parametrization. Finally, the 2011 

HFIP stream 1.5 web page will be previewed. 


Ensemble-based prediction and diagnostics during the PREDICT field experiement 

Sharanya J. Majumdar 1 , Ryan D. Torn 2 , Fuqing Zhang 3 

(smajumdar@rsmas.miami.edu) 

1 Rosenstiel School of Marine and Atmospheric Science, University of Miami; 

2 University at Albany, State University of New York; 

3 Department of Meteorology, Penn State University 

During the NSF-sponsored PRE-Depression Investigation of Cloud-systems in the 

Tropics (PREDICT) field experiment, which took place during August-September 2010, a 

variety of synoptic-scale, mesoscale and convective-scale products based on ensemble forecasts 

were disseminated. In addition to operational global ensemble forecasts provided by ECMWF 

and NCEP, new higher-resolution, data-assimilative Weather Research and Forecasting 

ensembles initialized using the Ensemble Kalman Filter (WRF/EnKF) were also run in real-time. 

With the primary focus of PREDICT being to test the 'marsupial' theory on how clusters of 

thunderstorms organize into tropical depressions, ensemble mean and probabilistic measures of 

low-level circulation and thickness anomaly were provided to yield quantitative estimates of 

fields relevant to genesis. Other products included probability distributions of vertical wind 

shear, relative humidity, and upper-level divergence, and spaghetti contours of the curvature of 

the flow via the Okubo-Weiss parameter. The utility of all these ensemble products will be 

presented for the disturbance that eventually became Hurricane Karl, together with preliminary 

evaluations of the ensembles' abilities to quantitatively predict metrics relevant to genesis. 


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Session 7 




Part 3 

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Technology Transfer in Tropical Cyclone Numerical Modeling – 

The role of the Developmental Testbed Center (DTC) 

Ligia Bernardet 1∗ % , Shaowu Bao 1,% , Christopher Harrop 1,% , Donald Stark 2 , Timothy Brown 1,% 

(ligia.bernardet@noaa.gov) 

1 NOAA Earth System research Laboratory – Global Systems Division, Boulder, CO 

2 National Center for Atmospheric Research, Boulder CO 

The Hurricane Weather, Research and Forecasting (HWRF) model is one of two NOAA 

operational regional numerical weather prediction (NWP) models for tropical cyclones. HWRF 

is an important component of the numerical guidance used at the National Hurricane Center for 

tropical storm forecasting. For that reason, it is critical that HWRF be continuously improved 

and uses state of the art research and developments in tropical NWP. 

The Developmental Testbed Center (DTC – dtcenter.org) has partnered with the NOAA National 

Centers for Environmental Prediction to work with the transfer of new technologies onto HWRF. 

The DTC is an organization with nodes at NOAA Earth System Research Laboratory and the 

National Center for Atmospheric Research that has as a mission bridging the gap between 

research and operations in several areas of numerical weather prediction. 

The DTC’s work in transferring new technology to HWRF follows two strategies. First, the DTC 

recognizes that the use of a single code base between research and operations facilitates the 

exchanges between the two groups. Over the last year, the DTC has worked with NOAA NCEP 

to merge the components of the HWRF model that are used operationally onto Community 

codes. This work has culminated with the transfer of a community model for operational 

implementation for the 2011 hurricane season. Since March 2010, the DTC has been providing 

code management and user support for HWRF (http://www.dtcenter.org/HurrWRF/users), 

having now reached 150 registered users. Our presentation will describe the process used to 

transfer the community model onto operations and the support that DTC provides to its users. 

The second strategy is to have the DTC maintain a functionally equivalent HWRF testing and 

evaluation infrastructure in order to assess new developments that have a potential for 

operational implementation in the short or medium term. We will present results of multipleseason 

forecasts of the Community HWRF model and will discuss the upcoming evaluations to 

be conducted at the DTC to test new developments that have a potential for operational 

implementation. 

% Also affiliated with the Cooperative Institute for Research in the Environmental Sciences, University of Colorado, 

Boulder, CO. 


Objective evaluation of 2010 HFIP Stream 1.5 candidates 

Louisa Nance, Christopher L. Williams, Michelle Harrold, Kathryn Newman, Paul Kucera, and 

Barbara Brown 

(nance@ucar.edu) 

National Center for Atmospheric Research, Boulder, CO 

The Hurricane Forecast Improvement Project (HFIP) provides the basis for NOAA and other 

agencies to coordinate hurricane research needed to significantly improve numerical guidance 

for hurricane forecasts. HFIP activities supporting the yearly upgrades made to operational 

numerical weather prediction (NWP) capabilities are referred to as “Stream 1”; whereas efforts 

taking multiple years to enhance operations are referred to as “Stream 2”. In 2010, HFIP and the 

National Hurricane Center (NHC) established a new, intermediate pathway to operations known 

as “Stream 1.5”. Stream 1.5 covers experimental models and/or techniques that NHC, based on 

prior assessments, wants to access in real-time during a particular hurricane season, but which 

cannot be made available to NHC by the operational modeling centers in conventional 

“production” mode. Stream 1.5 projects are run as part of HFIP’s annual “Demonstration 

Project”. To qualify, participation by a candidate project must be approved by HFIP 

management and the NHC. Part of the basis for this approval is demonstrated performance 

through extensive retrospective testing. The retrospective testing for the 2010 Stream 1.5 

candidates focused on a representative sample of 27 storms from the 2008 and 2009 hurricane 

seasons. Four modeling groups participated in this retrospective test activity: Geophysical Fluid 

Dynamics Laboratory (GFDL) – GFDL hurricane model, Mesoscale and Microscale 

Meteorology (MMM) division of the NCAR Earth System Laboratory (NESL) – Advanced 

Hurricane WRF (AHW), Naval Research Laboratory (NRL) – Couple Ocean/Atmosphere 

Mesoscale Prediction System - Tropical Cyclone (COAMPS-TC), and Florida State University 

(FSU) – Advanced Research WRF (ARW). This presentation will discuss the objective 

evaluation of the submitted retrospective forecasts that was conducted by the Tropical Cyclone 

Modeling Team (TCMT) located in the Joint Numerical Testbed (JNT) of NCAR’s Research 

Applications Laboratory (RAL). The presentation will briefly review the methodology used for 

this evaluation, summarize the high lights of the evaluation and discuss plans for the 2011 

Stream 1.5 retrospective testing. 


Hurricane Intensity and Structure Research Using NOAA's High Resolution Forecast 

Model and its Transition to Operations 

Sundararaman.G.Gopalakrishnan 1 , Frank Marks 1 and Vijay Tallapragada 1 

(gopal@noaa.gov) 

1 /AOML/NOAA/HRD; 2 NOAA/NCEP/EMC 

HWFRX is the high resolution, research version of the National Centers for Environmental 

Prediction’s (NCEP) Hurricane Weather Research and Forecasting model specifically adopted 

and developed jointly at NOAA’s Atlantic Oceanographic and Meteorological Laboratory 

(AOML) and Earth System Research Laboratory (ESRL) for studying the intensity change 

problem at 1-3 km model grid resolution. This modeling system is supported by NOAA's 

Hurricane Forecasting Improvement Project (HFIP). An overview of the model 

developments and the related research activities will be provided. As a part of the HFIP demo 

project a 3-km-resolution version of the HWRFX system was run using the operational HWRF 

initial conditions for the 2005, 2007, 2009 and 2010 seasons. Several sensitivity experiments on 

initial conditions, physics and resolution were also performed for at least a set of 89 cases of 

storms from those seasons. The seasonal performance of the model along with the results from 

the sensitivity experiments will be provided. A merger of the HWRFX and the operational 

version of the HWRF system, now dubbed as "HWRFV3.2" is under development. The 2012 

operational upgrade will potentially include a triply nested system operating at a scale of about 3 

km and is expected to provide improvements to structure and intensity predictions. We will 

provide a status report on this system. 


Progress Towards a High-Resolution HWRF Model 

Sam Trahan 1 , Vijay Tallapragada 1 , S.G.Gopal 2 , Xuejin Zhang 2 

(Samuel.Trahan@noaa.gov) 

1 NOAA NCEP EMC 

2 NOAA AOML HRD 

This presentation gives an overview of the joint NOAA EMC-HRD research towards developing 

a triple nested high-resolution hurricane forecasting system based on the EMC HWRF with 

upgrades from the experimental HRD HWRF-X and elsewhere. We show improvements in the 

representation of hurricane structure as a result of the higher resolution. We detail computational 

efficiency experiments that will eventually lead to operational implementation. We also 

overview upcoming work on improving the physics, initialization, ocean coupling and other 

model aspects to take advantage of the higher atmospheric model resolution and realize 

improved hurricane intensity and structure prediction. 


Evaluation and Improvements of Cloud and Precipitation Physics in 

the Operational Hurricane WRF Model at NOAA/EMC 

Yuqing Wang 

(yuqing@hawaii.edu) 

International Pacific Research Center and Department of Meteorology, University of Hawaii at 

Manoa 

The overall goal of this project is to evaluate and improve the cloud and precipitation 

physics used in the operational Hurricane Weather Research and Forecasting (HWRF) model 

developed in the Environmental Modeling Center (EMC) at the National Centers for 

Environmental Prediction (NCEP) of NOAA, achieving improved prediction of hurricane 

structure and intensity, including the size, by the HWRF model at NCEP/EMC. As the first step, 

we have implemented the current cloud microphysics scheme and convective parameterization 

scheme used in the HWRF model into TCM4 and compared the structure, intensity, and diabatic 

heating of the HWRF model cloud microphysics scheme with that used in TCM4. We have 

examined the possible effect of cumulus convective parameterization scheme in coarse model 

domains on the fine-resolution explicit simulations of hurricanes in TCM4. These comparisons 

have helped us identify the potential discrepancies of the current cloud and precipitation physics 

used in the HWRF model and provide the basis for our improvements of the HWRF cloud and 

precipitation physics. 

We have also examined the possible discrepancies in the dynamical core of the HWRF 

model in comparison with the simulation using the WRF_ARW dynamical core with the same 

model physics options. It is our purpose to see whether biases in the prediction of hurricane size 

and intensity by HWRF are related to the dynamical core. Hurricane Katrina (2005) was selected 

in the comparison. Our results show that although the NMM dynamical core simulated weaker 

hurricane intensity, it simulated the track considerably better in terms of the timing and location 

of landfall than the ARW dynamical core for this case. This indicates that the NMM dynamical 

core might capture the evolution of the large-scale environmental flow, which is the key to the 

accurate prediction of storm motion. However, the storm intensity is largely controlled by the 

inner core dynamics, which was not well represented by the numerical scheme in the NMM 

dynamical core. The difference in the vertical structure of the simulated storm suggests that some 

discrepancies between the simulations with different dynamical cores might be related to the 

difference in the vertical descretization. We also found that the dynamical core may affect the 

cloud microphysics to some degree. We also found that the dynamical core may affect the cloud 

microphysics to some degree. We thus suggest that a systematic diagnostics of the dynamical 

core of the NMM is required in order to improve the prediction of storm intensity and structure 

by HWRF. 


Controlling Factors of the Radius of Maximum Winds in HWRF 

Jian-Wen Bao, Sara A. Michelson, Sundararaman G. Gopalakrishnan 

(Jian-Wen.Bao@noaa.gov) 

NOAA/ESRL and NOAA/AMOL 

This presentation highlights major results from a series of numerical experiments with 

NOAA’s Hurricane WRF (HWRF) model. The purpose of the experiments is to investigate the 

sensitivity of the radius of maximum winds of an idealized tropical storm to the model’s internal 

controlling factors (such as the size of the initial vortex, cloud physics and vertical diffusion) and 

external conditions (such as the latitude-dependent Coriolis parameter). The model is initialized 

with a weak axisymmetric vortex disturbance in an idealized tropical environment that is 

favorable for the vortex disturbance to develop into a hurricane. The initial mass and wind fields 

associated with the weak vortex disturbance are obtained by solving the nonlinear balance 

equation for the given wind distributions of the initial vortex, and the prescribed background 

thermal sounding and winds. Results from the idealized HWRF sensitivity runs are compared in 

terms of the radius of maximum winds along with the azimuthally averaged storm structure and 

the surface wind-pressure relationships, to gain an insight into how to improve the model. 


Tropical Cyclone Inner-core Diagnostics 

Robert Rogers 1 , Paul Reasor 1 , S. Lorsolo 2 , and J. Zhang 2 

(Robert.Rogers@noaa.gov) 

1 NOAA/AOML Hurricane Research Division, Miami, FL 

2 CIMAS, University of Miami, Miami, FL 

Much work has gone toward evaluating the performance of numerical models using 

“traditional” metrics, e.g., position and intensity errors. As operational horizontal grid lengths 

approach 3 km (and eventually reach 1 km), the ability to represent many features within the 

inner core of tropical cyclones (TCs) increases. Robust evaluations of TC inner-core structure 

are therefore crucial to assess the realism of numerical simulations. A wealth of TC inner-core 

data collected and archived at the NOAA Hurricane Research Division (HRD) over many years 

provides an excellent opportunity for evaluating high-resolution numerical models. 

In this talk composites from observations (airborne Doppler and dropsondes) and 

simulations of multiple storms will be compared. These composites are key to providing 

statistically robust measures and evaluations of numerical models. The focus here is on several 

scales within the TC inner core – symmetric and asymmetric vortex-scale properties, convectivescale 

statistics, and boundary-layer structure. 


On the Characteristic Height Scales of the Hurricane Boundary Layer: Dropsonde 

Composite Analysis for the Purpose of Model Diagnostics 

Jun Zhang 1 Robert Rogers 2 , David Nolan 3 , Frank Marks 2 

(Jun.Zhang@noaa.gov) 

1 UM/CIMAS & NOAA/HRD, 2 (NOAA/HRD), 3 UM/RSMAS 

In this talk, we present composite analysis results using hundreds of GPS dropsonde data from 

13 hurricanes. We focus on the investigation of the characteristic height scales of the hurricane 

boundary layer. The height scales are defined in a variety of ways: the height of the maximum 

total wind speed, the inflow layer depth, and the mixed layer depth. The height of the maximum 

wind speed and the inflow layer depth are referred to as the dynamical boundary layer heights, 

while the mixed layer depth is referred to as the thermodynamical boundary layer height. The 

data analyses show that there is a clear separation of the thermodynamical and dynamical 

boundary layer heights. Consistent with previous studies on the boundary layer structure in 

individual storms, the dynamical boundary layer height is found to decrease with decreasing 

radius to the storm center. The thermodynamic boundary layer height, which is much shallower 

than the dynamical boundary layer height, is also found to decrease with decreasing radius to the 

storm center. The results also suggest that using the traditional critical Richardson number 

method to determine the boundary layer height may not accurately reproduce the height scale of 

the hurricane boundary layer. These different height scales reveal the complexity of the hurricane 

boundary layer structure that should be captured in hurricane model simulations. Methodology 

and preliminary results of using the dropsonde composites to evaluate the PBL scheme used in 

the Hurricane Weather Research and Forecast (HWRF) model are discussed. 


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Session 9 

ITOP/TCS-10: Coupled 

Air-Sea Observations and 

TC Predictions 

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Overview of the ITOP / TCS10 Program: Impact of Typhoons on the Pacific 

Eric A. D’Asaro 

(dasaro@apl.washington.edu) 

Applied Physics Laboratory and School of Oceanography, University of Washington, Seattle 

The Impacts of Typhoons on the Ocean in the Pacific (ITOP) program was a multinational 

field campaign that aimed to study typhoons and the ocean response to typhoons in the 

western Pacific Ocean. ITOP focused on understanding how the cold wake of a typhoon forms 

and dissipates, the air-sea fluxes for winds greater than 30 m/s, the impact of ocean eddies on 

typhoons and the physical and biogeochemical ocean response to typhoons, the surface wave 

field under typhoons, and typhoon genesis and forecasting. 

An array of 10 ocean moorings, including detailed air-sea flux instrumentation, was 

deployed from July to October, 2010. Two C-130J aircraft of the Air Force Reserve 53 rd WRS 

operated from Guam from Aug. 20 to Oct. 20, 2010, working in cooperation with the Taiwanese 

DOTSTAR program. They conducted storm reconnaissance, deploying ~700 dropsondes and 

~850 AXBTs in the vicinity of typhoons and deployed 89 oceanographic drifters and floats 

ahead of typhoons and into their wakes. US and Taiwanese research vessels made measurements 

in the wake of typhoons making ~3500 CTD profiles and deploying 10 long-term autonomous 

gliders. Operations were directed from a control center at the Naval Postgraduate School. 

ITOP sampled the structure of and ocean response to 3 typhoons: Fanapi, Malakas and 

supertyphoon Megi, one of the strongest typhoons every measured (885 mbar). Detailed 

measurements of the air-sea fluxes were obtained in Fanapi and Megi. The ocean response to 

typhoons was complicated by strong internal tides in this region. All three typhoons made strong 

cold wakes. Megi’s wake was very narrow, 20 km across, reflecting the small size of the storm, 

while Malakas’ ranged from 100-250 km. The evolution of Fanapi’s wake was followed for a 

month. The surface signature of the wake rapidly diminished due to surface warming, but a thick 

cold subsurface component lasted for at least 3 weeks and was advected around a cyclonic eddy. 

ITOP was supported by the Office of Naval Research and the Taiwan National Science Council. 


Multi-scale Observations of Cloud Clusters and Tropical Cyclones in ITOP/TCS10 

Shuyi S. Chen, B. Kerns, E. Ryan, and C. Lee 

(schen@rsmas.miami.edu) 

RSMAS/University of Miami 

The goal of the Impact of Typhoon on Ocean over the Pacific (ITOP) and Tropical Cyclone 

Structure 2010 (TCS10) is to better understand and predict TC formation and intensity change 

through a comprehensive observation of TC structure and its oceanic and atmospheric 

environment over a broad spatial and time scales. An objective cloud-cluster tracking method is 

used to identify the TC precursor clusters using hourly satellite IR images over the entire West- 

Central Pacific basin. By tracking all cloud clusters, we are able to objectively determine both 

developing and non-developing TCs, which have been a one of the most difficult problem in 

understanding of formation (genesis) of TCs in the past, especially the lack of objective method 

for determining non-developing TCs. Comparing with results from previous years (2003-2009), 

2010 consists of more long-lived cloud clusters that do not develop into TCs, even though some 

apparent large-scale conditions such as warm SST and synoptic wave-like disturbances are 

abundant. Composite of the environmental conditions for developing vs. non-developing cases 

using the global analysis fields and in situ airborne dropsonde and AXBT data are used to 

quantify the mesoscale and large-scale “forcing” for TCs. The ITOP/TCS10 field experiments 

were designed to follow the developing TC throughout their lifecycle with extensive 

observations of pre-, during- and post-TC oceanic and atmospheric conditions. More than 800 

GPS dropsondes and 1000 AXBTs/AXCTs as well as drifters and floats were deployed in TCs 

from August-October 2010, including Typhoon Fanapei and Supertyphoon Megi. Some 

preliminary analysis and implication for coupled TC prediction model development and 

verification will be discussed. Furthermore, a comparison of TC activities between the western 

Pacific and Altantic basins using the cloud-cluster tracking analysis will be presented. 


The Challenge of Measuring the Atmosphere-Ocean Interface in Tropical Cyclones: 

Observations from Air-Deployed Drifters 

Jan Morzel 1 , Luca Centurioni 2 , P.P Niiler 2 

(jan@rosettaconsult.com) 

1 Rosetta Consulting; 2 Scripps Institution of Oceanography 

Since 2003, air-deployed drifters have been used to make measurements of upper ocean 

temperature, surface currents, atmospheric pressure, wind velocity, and, more recently, of 

subsurface ocean currents and solar radiation, within tropical cyclones and in their cold wakes. 

The co-ordination of multiple projects sponsored by the Office of Naval Research and by NOAA 

has led to the accumulation of a dataset that includes drifter observations of six hurricanes and 

four typhoons, covering the Cat 1 through Cat 5 range. The air-deployment success rate of the 

drifters is 93%. 

Drifters are typically air-deployed along a 400 km line, 18 to 24 hours ahead of the tropical 

storm. The spatial separation of the drifter array ranges from 30 to 50 km. Atmospheric pressure, 

sea surface temperature and surface winds are measured every 15 min. The data are transmitted 

in real-time through the Argos and Iridium satellite systems and are routinely placed on the 

Global Telecommunication System. 

We focus on oceanic and atmospheric observations obtained during typhoon Fanapi in 

September 2010 during the ITOP/TCS10 field project in the Western Pacific. We discuss wind 

and atmospheric pressure measurements obtained with a new meteorological package, as well as 

upper ocean temperature changes. The preliminary results show that on 09-18-2010 between 

0030Z and 0400Z Fanapi’s minimum recorded pressure was 940 mbar and it left a cold wake 

approximately 150 to 200 km wide with a maximum surface cooling of 2.5 °C 

The first order challenge for forecasting and warning centers consists of accurately predicting 

intensity changes of tropical cyclones. Providing quality measurements of the upper ocean 

thermal structure is therefore crucial. The comprehensive drifter dataset represents an 

opportunity to improve data assimilation, to initialize forecast models and to validate research 

and operational models. 


Pre-Genesis Monitoring of the 3-D Atmospheric and Oceanic Environment Via High 

Altitude Aircraft Observations 

Jeff Hawkins 1 , Peter Black 2 , Pat Harr 3 , Russ Elsberry 3 

(Jeffrey.Hawkins@nrlmry.navy.mil) 

1 Naval Research Laboratory; 2 Science Applications International Inc; 

3 Naval Postgraduate School 

The Tropical Cyclone Structure (TCS-08) and the Impact of Typhoons on the Ocean in the 

Pacific (ITOP) field programs enabled the first two tests of high altitude (300 MB) deployment 

of dropsondes and AXBTs into pre-genesis, incipient tropical cyclone (TC) systems within the 

western North Pacific basin (WPAC). This sampling strategy enabled a unique view of the three 

dimensional (3-D) atmospheric (winds, temperature and moisture) and oceanic thermal 

environments. Data sets from both developing and non-developing tropical systems were intercompared 

through the use of the Air Force WC-130J data sets, which include dropsondes, 

Stepped Frequency Microwave Radiometer (SFMR), airborne radar, and flight level parameters, 

MTSAT-derived automated cloud motion winds, NRL P-3 Eldora 3-D winds (TCS-08), and 

satellite-derived ocean surface wind vectors (QuikSCAT – TCS-08 only, ASCAT, and WindSat). 

Aircraft flights were designed to overlap with satellite over-pass times as close as possible. In 

addition, satellite-derived total precipitable water (TPW), a measure of low/mid-level moisture 

content which maps mesoscale and synoptic scale features, was utilized to observe the potential 

of dry- and moist-air entrainment into the inner vortex. This combination of sensors allowed the 

aircraft-derived observations to validate satellite-derived observations of ocean surface and midlevel 

winds as well as sea surface temperature (SST) and subsurface ocean heat content (OHC). 

During August 2008, TCS-08 candidate systems included many weak convective clusters as the 

western Pacific basin experienced an unusual ‘TC drought’ and an anomalous circulation pattern. 

Organized convective activity was suppressed and the monsoon trough was absent as low-level 

easterly flow predominated. Several wave-like systems entered the TCS-08 Guam domain from 

the east and were investigated by the WC-130J and NRL P-3 aircraft. ITOP conditions during 

2010 included additional pre-genesis cases near Guam of several systems that later evolved into 

significant TCs. 

Passive microwave imagers were able to augment the TCS-08 and ITOP aircraft data sets by 

mapping the rainfall and convective cloud cluster patterns during many daily overpasses. The 

combination of both operational and research microwave satellite sensors (SSM/I, SSMIS, TMI, 

AMSR-E, and WindSat) provided frequent temporal observations of convective system 

evolution. The temporal sampling from the microwave imagers provided the large-scale context 

in mapping convective organization of the three tropical systems using WC-130J recorded radar 

video and NRL P3 Eldora Doppler radar data (TCS-08), but does not provide the 3-D structure, 

nor spatial details needed to appropriately understand the full 3-D storm environment. 

Preliminary analysis of the WC-130J dropsondes, AXBTs, and satellite digital data sets indicate 

complicated 3-D atmospheric and oceanic structures can be monitored by the high altitude WC- 

130J dropsonde square spiral flight patterns and effectively detail critical differences between 


low, mid and upper-level wind, temperature and moisture variables as the genesis system 

struggles within the sometimes very harsh environmental conditions. Important information 

pertaining to wind shear and possible decoupling between the low and mid level vortex and the 

extent of dry air intruding into or near the system’s inner core can only be accurately obtained 

via these high altitude 3-D dropsonde measurements that systematically cover the entire storm 

grid and not just the periphery as currently accomplished within some NOAA G-IV flights. 

These 3-D atmospheric data sets have the potential to also initialize and help validate multiple 

ongoing TC mesoscale numerical weather prediction (NWP) forecast model diagnoses and 

forecast efforts as the community attempts to improve predictions of genesis, track, and intensity. 

In addition, the AXBT data has provided the means to effectively map the oceanic thermal front 

and eddy field and help us factor in OHC impacts on storm intensification and decay, not 

otherwise accounted for in previous WPAC studies. 


Ocean observations in developing and mature TC’s based on a new airborne observing 

strategy: 'Combo' deployments of AXBT’s and GPS dropsondes from long-endurance, 

multi-altitude reconnaissance flights 

P. G. Black 1 and J. D. Hawkins 2 

(peter.black.ctr@nrlmry.navy.mil) 

1 Science Applications International Corporation/Naval Research Laboratory; 2 Naval Research 

Laboratory 

The first ‘combo’ deployment of AXBTs and dropsondes into pre-genesis, and mature tropical 

cyclones (TC’s) within the Western North Pacific (WPAC) basin was conducted during the 

TPARC-Tropical Cyclone Structure (TPARC/TCS-08) field program. This strategy was repeated 

again during the Interaction of Typhoons over the Pacific experiment (ITOP/TCS10) in 2010. 

This sampling strategy enabled a unique view of the three- dimensional (3-D) oceanic thermal 

and atmospheric environments in evolving tropical systems to be obtained. Coupled with the 

low-level ocean buoy/float deployment capability of the AFRC WC-130J aircraft, its longendurance 

in excess of 12-hours and high-altitude capabilities (300 mb) demonstrates a new era 

in TC operational ocean feature observation capabilities for initialization and validation of new 

coupled air-sea TC models such as the NRL coupled COAMPS-TC model, brought on line for 

the first time during ITOP/TCS10. 

Preliminary analysis of the TPARC and ITOP WC-130J AXBT data indicated that three of four 

systems that developed into typhoons in 2008 and two of three systems in 2010 developed within 

the WPAC oceanic region referred to as the ‘Southern Eddy Zone' between 16-24 N. In 

TPARC/TCS08, AXBT data for one case (Jangmi) showed rapid intensification (RI) over a 

warm eddy and subsequent rapid decay (RD) over a cold eddy while during ITOP/TCS10, 

another case (Fanapi) showed rapid development over a warm eddy. While underlying ocean 

conditions seemed not to be a factor in TC formation, or lack thereof, subsequent development 

did appear to depend on subsurface ocean eddy conditions, a result that makes monitoring these 

ocean conditions for coupled model use an important new consideration in TC observational 

requirements. 

We suggest that this sampling strategy may prove effective in meeting emerging observational 

requirements for model initialization and validation in the Atlantic Basin as the use of coupled 

TC prediction models grows. This strategy of flying high in weak systems rather than flying low 

looking for closed circulations takes advantage of the high altitude and long range capability of 

the WC-130J aircraft and provides the ability to simultaneously map vertical atmospheric 

structure searching for signatures of mid-level as well as low-level spin-up at the earliest possible 

time while also mapping the surface wind field through use of the new Stepped Frequency 

Microwave Radiometer (SFMR), also flown on the WC-130J aircraft. Furthermore, simultaneous 

ocean vertical structure profiles reveal signatures of ocean eddies that may impact TC 

development and subsequent intensification. This type of strategy, especially in concert with G- 

IV surveillance flights in the storm environment would bring a powerful new set of observations 

into play that could be ideal not only for coupled model initialization and validation but for 

forecaster diagnostics for subsequent TC intensification or decay. 


An overview of COAMPS-TC Forecasts and Targeting for ITOP 

Sue Chen, James Doyle, Richard Hodur, Hao Jin, James Cummings, and Jerome Schmidt 

(Sue.Chen@nrlmry.navy.mil) 


An unprecedented typhoon field campaign that combined state-of-the-art observations in the 

atmosphere and ocean (“Tropical Cyclone Structure (TCS)-10” /“Impact of Typhoons on the 

Ocean in the Pacific (ITOP)”) was conducted in the Western Pacific during the summer of 2010. 

Four different configurations of the Coupled Ocean/Atmosphere Mesoscale Prediction System- 

Tropical Cyclone (COAMPS-TC) were used to provide typhoon genesis, track, and intensity 

forecasts in real-time for TCS-10/ITOP. These COAMPS-TC configurations were (a) a fixeddomain 

(27 and 9 km nested grids) two-way air-sea coupled COAMPS-TC area (INVEST), (b) 

an atmosphere-only version of COAMPS-TC using a triply-nested grid down to 5 km that 

automatically moved with the tropical cyclone, (c) the atmosphere-ocean coupled COAMPS-TC 

system that used the same nested grids for the atmosphere as in (c), and (d) the COAMPS-TC 

atmospheric adjoint model coupled with a simple ocean mixed layer (ADJOINT),. The 

ADJOINT configuration was used to assist in determining where targeted observations could be 

employed in both the atmosphere and the ocean, while the INVEST configuration was used for 

daily assessments of typhoon genesis potential. The atmosphere-only and the coupled 

COAMPS-TC configurations were used to provide forecast track and intensity information, and 

were only activated when a typhoon warning message was issued by the Joint Typhoon Forecast 

Center. The major findings and results from these four COAMPS-TC forecast exercises include: 

(i) the INVEST configuration provided a three-day warning lead time for the genesis location of 

typhoon Fanapi; (ii) continuous assimilation of the ocean observations in the INVEST runs 

reduced the ocean model sea surface temperature bias which, in turn, improved the ocean forcing 

to the atmospheric model; (iii) upgraded microphysical and radiation processes improved the 

surface radiative forcing for the ocean model; and (iv) the seasonal-averaged (8 typhoons) 

intensity error was larger in the coupled COAMPS-TC forecasts than in the uncoupled 

COAMPS-TC forecasts, but the coupled COAMPS-TC exhibited a slightly smaller cross-track 

bias than the uncoupled COAMPS-TC in the 48-96 hour forecast period; and (v) the ADJOINT 

exhibits complex patterns of sensitivity to ocean-mixed layer depth for storms reaching typhoon 

strength along with large sensitivity to the low-level atmospheric moisture near typhoon Megi. 

More detailed discussions on the use, forecast performance, and lessons learned from our 

applications of the ADJOINT, INVEST, and the uncoupled and coupled COAMPS-TC 

configurations for eight typhoons during the 2010 season will be presented. 


Multi-Model Coupled Air-Sea Forecasts of Typhoons during ITOP 

Brandon Kerns, Shuyi S. Chen, and Chiaying Lee 

(bkerns@rsmas.miami.edu) 


In support of the Impact of Typhoons on the Ocean in the Pacific (ITOP) experiment, 

high-resolution coupled models were run in a semi-operational setting in real time at the 

University of Miami Rosenstiel School of Marine and Atmospheric Science (RSMAS) during the 

ITOP dry run from Sep-Oct 2009 and field phase from August-October 2010. The highresolution 

models include the University of Miami Coupled Model (UMCM) and the coupled 

WRF (CWRF) with triply nested grids of 12, 4, and 1.3-km grid spacing. The coupled models 

include the fully coupled atmospheric, ocean and wave model components. A multi-model, highresolution 

prediction system used in ITOP consists of UMCM and CWRF that are run with 

various initial and boundary conditions from several operational global models including GFS, 

ECMWF, NOGAPS, JMA, and HYCOM. The coupled models provide not only the storm track, 

intensity and structure forecasts, but also the surface waves and ocean temperature and current 

fields in typhoons. The air-sea coupled forecasts were used in near real time to aid the 

deployment of the ITOP atmospheric and oceanic instrumentation from the C-130 aircraft and 

ships. Preliminary results from the coupled model forecasts and verification statistics from eight 

typhoons will be presented at IHC. Implications and potential applications for hurricane 

reconnaissance and prediction in the Atlantic will be discussed. 


S 

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Session 10 

Other Research to 

Improve the Prediction of 

Tropical Cyclone Intensity 

and Structure, Track, 

Precipitation, and Inland 

Inundation, 

Part 1 

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Hurricane and Severe Storm Sentinel (HS3): A Multi-year Investigation of Atlantic 

Hurricanes 

Scott A. Braun 1 , Paul A. Newman 1 , Marilyn Vasques 2 

(scott.a.braun@nasa.gov) 

1 NASA/GSFC; , 2 NASA/ARC 

HS3 is a five-year mission specifically targeted to enhance our understanding of the processes 

that underlie hurricane intensity change in the Atlantic Ocean basin. The HS3 science questions 

can be distilled down to the extent to which either the environment or processes internal to the 

storm are key to intensity change. Is storm formation and intensification mainly a result of 

characteristics of the large-scale environment or internal processes? Are these internal processes 

driven by large-scale forcing or do they act independently of this forcing? 

The HS3 objectives are: 

• To obtain critical measurements in the hurricane environment in order to identify the role of 

key factors such as large-scale wind systems (troughs, jet streams), Saharan air masses, African 

Easterly Waves and their embedded critical layers (that help to isolate tropical disturbances from 

hostile environments). 

• To observe and understand the three-dimensional mesoscale and convective-scale internal 

structures of tropical disturbances and cyclones and their role in intensity change. 

The mission objectives will be achieved using two Global Hawk (GH) Unmanned Airborne 

Systems (UASs) with separate comprehensive environmental and over-storm payloads. The GH 

flight altitudes (>16.8 km) allow overflights of most convection and sampling of uppertropospheric 

winds. Deployments from Goddard’s Wallops Flight Facility and 30-hour flight 

durations will provide coverage of the entire Atlantic Ocean basin, and on-station times up to 10- 

24 h depending on storm location. Deployments will be in September of 2012 and from mid- 

August to mid-September 2013-2014, with ten 30-h flights per deployment. 

HS3’s suite of advanced instruments will measure key characteristics of the storm 

environment and its internal structures. The measurements include: 

Measurements from the Environmental GH Payload 

• Continuous sampling of temperature and relative humidity in the clear-air 

environment from the scanning High-resolution Interferometer Sounder (S-HIS). 

• Continuous wind profiles in clear air from the TWiLiTE instrument. TWiLiTE is a 

direct detection Doppler lidar capable of measuring the motion of air molecules in clear 

air environments. 


• Full tropospheric wind, temperature, and humidity profiles from the Advanced 

Vertical Atmospheric Profiling System (AVAPS) dropsonde system, which is capable 

of releasing up to 100 dropsondes in a single flight. 

• Aerosol and cloud layer vertical structure from the Cloud Physics Lidar (CPL). 

Measurements from the Over-Storm GH Payload 

• Three-dimensional wind and precipitation fields from the High-altitude Wind and 

Rain Airborne Profiler (HIWRAP) conically scanning Doppler radar. 

• Surface winds and rainfall from the Hurricane Imaging Radiometer (HIRAD) multifrequency 

interferometric radiometer. 

• Measurements of temperature, water vapor, and liquid water profiles, total 

precipitable water, sea-surface temperature, rain rates, and vertical precipitation profiles 

from the High-Altitude MMIC Sounding Radiometer (HAMSR). 


2011 Plans for NOAA’s Intensity Forecasting Experiment (IFEX) 

Shirley T. Murillo 

(Shirley.Murillo@noaa.gov) 

NOAA/AOML/HRD 

We continue to address the goals set forth by NOAA’s Intensity Forecasting Experiment 

(IFEX). IFEX aims to collect observations throughout the tropical cyclone (TC) life cycle, 

develop and refine measurement technologies for real-time monitoring of TC structure and 

intensity, and improve understanding of the physical processes important in TC intensity change. 

This season our focus will be on strengthening the NOAA intra-agency partnership among HRD, 

AOC, EMC and NESDIS, as well as a new effort to enhance interactions between HRD and 

NHC. Plans for the 2011 field program, including how these interactions will impact it, will be 

presented. 


Estimating Tropical Cyclone Intensity from Infrared Image Data 

Elizabeth A. Ritchie 1 , Miguel F. Piñeros 2 , J. Scott Tyo 2 , and Genevieve Valliere-Kelley 1 

(ritchie@atmo.arizona.edu) 

1 Department of Atmospheric Sciences, University of Arizona; 2 College of Optical Sciences, 

University of Arizona 

A near real-time objective technique for obtaining features associated with the shape and the 

dynamics of cloud structures embedded in tropical cyclones from satellite infrared images is 

described. As the tropical cyclone develops from an unstructured cloud cluster and intensifies 

the cloud structures become more axisymmetric about an identified reference point. Using 

variables derived from remotely-sensed IR data, the technique calculates the gradient of the 

brightness temperatures to measure the level of symmetry of each structure and this level of 

symmetry characterizes the degree of cloud organization of the tropical cyclone. Previous results 

have shown that the technique provides a reasonable objective, independent measure of the 

intensity of the tropical cyclone. 

In this presentation, seventy-eight tropical cyclones from the 2004-2009 seasons are used to both 

train and independently test the intensity estimation technique. Two independent tests are 

performed to test the ability of the technique to accurately estimate tropical cyclone intensity. 

Results from these tests will be presented. 


Airborne Surface Water and Ocean Topography Mapping System 

James Carswell and D. Moller 

(carswell@remotesensingsolutions.com) 

Remote Sensing Solutions 

A long history of spaceborne radar altimetry observations of the ocean surface has revolutionized 

oceanography enabling significant advances in our understanding of global ocean circulation 

[e.g., Fu and Cazenave, 2001]. More recently these measurements (in the last decade) have been 

extended to provide elevation measurements of land surface water bodies (ie lakes, rivers and 

floodplains) [e.g. Birkett 1998; Alsdorf et. al. 2007a]. Despite the significant contributions of 

these observations, the fundamental limitation presented is the lack of coverage that a nadirlooking 

sensor can provide with gaps between satellite tracks of 200-300km. The result is that 

smaller scale features (e.g., oceanic mesoscale processes) are not resolved and many rivers and 

lakes are not observed altogether [Alsdorf et.al. 2007b]. 

In response the NRC Decadal Survey acknowledged not only the compelling science needs, 

but also the measurement commonality between the ocean and surface water communities by 

recommending the Surface Water Ocean Topography satellite mission (SWOT). To satisfy the 

high-resolution sampling requirements needed for surface water hydrology, and the high 

accuracy requirements for the oceanography, the primary SWOT instrument is a Ka-band Radar 

Interferometer (KaRIN). This solution is capable of simultaneously meeting coverage, accuracy 

and resolution requirements and enhances greatly the science achievable from a traditional 

profiling altimeter. However the uniqueness of this solution, and application, means there 

remain some specific questions for which there currently exists little or no supporting data. 

In this paper we present the Ka-band SWOT Phenomenology Airborne Radar (KaSPAR). 

This multi-baseline Ka-band InSAR will serve to provide the necessary measurements to address 

key SWOT mission risk items. With centimeter-scale precision, its ability for map ocean and 

surface water topography over a wide swath (near nadir to 25 degrees incidence), KaSPAR can 

provide unique high-resolution topography maps for directly observing storm surge caused by 

tropical storms. With its ability to map radial velocity as well, the surface water velocity and 

topography observations may also provide essential observations of coastal and inland 

inundation. These applications and KaSPAR measurement capabilities will be described. 

[Alsdorf et. al. 2007a] D. Alsdorf, Feu L. L, N. Mognard, A. Cazenave, E. Rodriguez, D. 

Chelton, D. Lettenmaier, Measuring Global Oceans and Terrestrial Freshwater From Space, 

EOS Transactions, American Geophysical Union, no. 24, pp. 25, 2007 

[Alsdorf et.al. 2007b] D. Alsdorf, E. Rodriguez, and D. P. Lettenmaier, Measuring surface water 

from space, Rev. Geophys., 45, RG2002 doi:10.1029/2006RG000197. 

[Birkett 1998] C.M. Birkett, Contribution of the TOPEX NASA radar altimeter to the global 

monitoring of large rivers and wetlands, Water Resources Research, 34, 1223-1239, 1998. 

[Fu and Cazenave, 2001] L. L. Fu, A. Cazenave Eds., Altimetry and Earth Science, A Handbook 

of Techniques and Applications, vol. 69 of International Geophysics Series, Academic Press, 

London, 2001 


The Experimental HWRF-HEDAS system: Model Evaluation in Preparation for Satellite 

Microwave Data Assimilation Inside the Hurricane Precipitation Area 

Svetla Hristova-Veleva 1 , Sundararaman Gopalakrishnan 2 , 

Tomislava Vukicevic 2 , Ziad Haddad 1 and Thiago Quirino 2 

(Svetla.Hristova@jpl.nasa.gov) 

1 Jet Propulsion Laboratory, California Institute of Technology; 2 NOAA/HRD/AOML 

Over the last two decades, data assimilation of satellite observations outside precipitation has 

lead to significant improvement in the ability of global models to represent the large-scale 

synoptic environment. This has resulted in measured improvement in the hurricane track 

forecast skills of the global models. However, improving the accuracy of hurricane intensity 

changes remains a very challenging problem. The main source of error for the large-scale 

models is their limited ability, due to the use of convective parameterizations, to resolve 

convective scale events and their interaction with the large-scale environment. Regional models 

have the resolution, and the physics to properly represent the convective processes. However, 

even today, there is large uncertainty regarding the assumptions used by the convective-scale 

parameterizations (e.g. parameterizations of the microphysical processes, the boundary layer 

processes and the ocean-atmosphere fluxes). 

Assimilation of satellite observations inside the precipitation presents the next opportunity for 

hurricane intensity forecast improvements. It offers two benefits: the ability to improve the 

model forecasts through constantly pushing the model toward the observed precipitation 

structures; the ability to improve the model physics through parameter estimation as part of the 

data assimilation. 

The data to be assimilated could be either the satellite-based retrievals of geophysical 

parameters, or, the observed radiances themselves. Assimilation of geophysical parameters is 

often easier since they are more closely related to the state variables. However, instantaneous 

satellite retrievals carry a lot of uncertainty. Assimilating the observed radiances is the more 

promising approach at the moment. However, to allow the model to efficiently assimilate the 

observed data, we need to first assure that the model-produced satellite observables compare well 

to the observations themselves. 

To facilitate the model evaluation, we are developing the Tropical Cyclone Information System 

(TCIS- http://topicalcyclone.jpl.nasa.gov). As part of TCIS, a dedicated portal was developed to 

facilitate the NASA/NOAA/NSF hurricane field campaigns of 2010 (http://grip.jpl.nasa.gov). 

We used it to identify a number of cases to allow the evaluation of different hurricane forecasts. 

In particular, we focused on evaluating the performance of the Experimental version of HWRF 

(HWRFX) in forecasting the evolution of hurricane Earl. In a previous study we used the model 

forecast of the thermodynamic and hydrometeor fields to forward simulate satellite observables 

(microwave brightness temperatures). We compared the overall structure of the observed and 

the forecasted storms as depicted by the brightness temperatures at 37 and 89 GHz channels. We 

found that the model was highly capable in depicting the 2D structure of the precipitation field 

and its evolution. However, the previous study was mostly qualitative. 


In this study we go further and perform a statistical comparison of the observed and simulated 

brightness temperatures. We evaluate their distributions as a function of the distance from the 

storm center. We look at the joint multi-frequency distributions of simulated and observed 

brightness temperatures to evaluate whether the vertical structure of the precipitation is properly 

reflected in the simulated storms. As part of this study, we also evaluate the impact of 

microphysical assumptions as manifested in the brightness temperatures of an ensemble WRF 

(ARW) simulations, each member using different assumptions about the hydrometeor’s particle 

size distributions. Ongoing plans include developing composites from satellite observations to 

facilitate the model evaluation. The goal is to point toward a more realistic set of assumptions 

that would produce simulations with closer-to-the-observed radiometric signatures. Assuring a 

close comparison between observed and modeled radiances in precipitation is the first, and very 

important, step toward an effective assimilation of satellite observations in the HWRFX system. 

For this purpose the Hurricane EnKF Data Assimilation System (HEDAS) that is currently 

developed at NOAA's hurricane research division is proposed to be used. 


Hurricane center-fixing with the Automated Rotational Center Hurricane Eye Retrieval 

(ARCHER) method 

Anthony Wimmers, Christopher Velden 

(wimmers@ssec.wisc.edu) 

Cooperative Institute for Meteorological Satellite Studies (CIMSS) 

University of Wisconsin-Madison 

Precise center-fixing of tropical cyclones (TCs) is critical for operational forecasting, intensity 

estimation and visualization. Current procedures are usually performed with manual input from a 

human analyst, using multispectral satellite imagery as the primary tools. While adequate in 

many cases, subjective interpretation can often lead to variance in the estimated center positions. 

In this paper we present an objective, robust algorithm for resolving the rotational center of TCs: 

the Automated Rotational Center Hurricane Eye Retrieval (ARCHER). The algorithm finds the 

center of rotation using spirally-oriented brightness temperature gradients in the TC banding 

patterns in combination with gradients along the ring-shaped edge of a possible eye. It is 

calibrated and validated using 85-92 GHz passive microwave imagery because of this 

frequency's relative ubiquity in TC applications. However, similar versions of ARCHER are also 

shown to work effectively with 37 GHz and infrared imagery of TCs. In TC cases with estimated 

low to moderate vertical wind shear, the mean accuracy of the ARCHER estimated center 

positions is 17 km (9 km for Category 1-5 hurricanes). In cases with estimated high vertical 

shear, the accuracy of ARCHER is 31 km (21 km for Category 2-5 hurricanes). Other structure 

parameters retrieved from this algorithm such as eye radius and eyewall brightness temperature 

are shown to have important value for intensity estimation. 


Intraseasonal to Seasonal Prediction of Tropical Cyclogenesis: 

A Statistical-Dynamical Forecast System 

Tom Murphree and David Meyer 

(murphree@nps.edu) 

Department of Meteorology, Naval Postgraduate School 

We have developed a statistical-dynamical prediction system for forecasting the 

probability of tropical cyclone (TC) formation at intraseasonal to seasonal scales and 2.5° 

horizontal resolution across the western North Pacific (WNP), with lead times out to 90 days. 

We use five large scale environmental factors (LSEFs) to represent the favorability of the climate 

system for tropical Cyclogenesis (low level relative vorticity, sea surface temperature, vertical 

wind shear, upper level divergence, and planetary vorticity). We use logistic regression to 

develop a statistical model representing the probability of TC formation based on the LSEFs. 

Data for the model development was obtained for the LSEFs from the NCEP R2 reanalysis, and 

for the corresponding TC activity from the JTWC best track data set. We use the NCEP Climate 

Forecast System (CFS) to obtain forecasts of the LSEFs at lead times of several days to several 

months, which we then use to force the regression model. The forecasts are ensemble means 

based on extensive ensembling of individual forecasts with multiple initial conditions and 

multiple lead times. 

We have conducted independent hindcasts for 1982-2008 which show the forecast system 

has skill and potential value to risk adverse customers (e.g., positive Brier skill scores, skillful 

ROC values). For 2009 and 2010, we have generated and verified forecasts out to leads of 90 

days. The skill of these forecasts is very positive, as indicated by several metrics. For example, 

for 2009, the 30 day lead forecasts had a probability of detection (POD) of 0.81 and a Heidke 

skill score (HSS) of 0.38. For 2010, the 90 day lead forecasts had a POD of 0.82 and a HSS of 

0.26 (the 2010 skill results are preliminary until the release of the JTWC best track data in 2011). 

The 2009 and 2010 forecasts also correctly predicted several intraseasonal and interannual 

variations. For example, the 30-90 day lead forecasts for 2010 forecasted a northward and 

westward shift in the location of the main formation region from its long term mean position, and 

much lower formation probabilities than normal, consistent with the observed formations for 

2010 and with the development of La Nina conditions in 2010. These formation anomalies were 

forecasted first by the 90 day lead forecasts issued in Mar-May 2010, three (five) months prior to 

the first La Nina watch (advisory) issued by NOAA/CPC. 

We have also developed a corresponding system for forecasting North Atlantic TC 

formations, with positive early results. We are presently upgrading the forecast system to take 

advantage of NCEP’s recently released and higher resolution Climate Forecast System 

Reanalysis (CFSR) and Climate Forecast System version 2 (CFSv2). 


S 

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Session 11 

Other Research to 

Improve the Prediction of 

Tropical Cyclone Intensity 

and Structure, Track, 

Precipitation, and Inland 

Inundation, 

Part 2 

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International Best Track Archive for Climate Stewardship (IBTrACS) 

activities at NOAA’s NCDC 

Kenneth R. Knapp a , Howard Diamond a , Ethan J Gibney c , Paula A. Hennon c , Michael C. Kruk c 

(Ken.Knapp@noaa.gov) 

a 

NOAA/NCDC, b I.M. Systems Group, Inc., Asheville, NC, c STG, Inc. 

The International Best Track Archive for Climate Stewardship (IBTrACS) is a project at 

NOAA’s National Climatic Data Center under the auspices of the World Data Center for 

Meteorology – Asheville to collect and disseminate the historical tropical cyclone best track data 

from all available agencies, merging the disparate data sets into one comprehensive product for 

the user community. One of the goals of the project is to maintain open data processing methods, 

so that desired user feedback on data quality is more easily collected. In addition, data 

provenance is completely recorded so all observations and corrections, either through rigorous 

quality control or user feedback, may be attributed to their source. Data are available in various 

formats to accommodate the diverse needs of the tropical cyclone data user community. The 

presentation will summarize the purpose of the project, recent accomplishments and the future 

direction of IBTrACS. More information on IBTrACS is available at 

http://www.ncdc.noaa.gov/oa/ibtracs/ 


Dry Air in the Tropical Cyclone Environment 

Jason P. Dunion 1 , Greg Tripoli 2 

(Jason.Dunion@noaa.gov) 

1 University of Miami/RSMAS/CIMAS - NOAA/AOML/HRD; 2 University of Wisconsin- 

Madison 

Infrared and microwave satellite imagery has steadily improved our ability to detect dry air in the 

environments of tropical disturbances. However, forecasting when and how low to mid-level dry 

air will interact with these systems remains a difficult challenge. This presentation will discuss 

details of diagnosing interactions between low to mid-level dry air and tropical disturbances (i.e. 

arc cloud formation), trajectory analyses that may provide insight as to where and when a dry air 

intrusion will take place, and idealized simulations that further investigate trajectories of dry air 

intrusions into tropical cyclones (TCs). 

When a dry air intrusion interacts with tropical convection, significant arc cloud events are often 

spawned. Although arc clouds are common features in mid-latitude thunderstorms and MCSs, 

they have only occasionally been noted in TC environments (Knaff and Weaver 2000). Arc 

clouds denote the presence of a density current that forms when dry middle level (~600-850 hPa) 

air has interacted with precipitation. The convectively-driven downdrafts that result can reach 

the surface/near-surface and spread out from a thunderstorm’s convective core. It is hypothesize 

that the mid-level moisture found in the moist tropical North Atlantic sounding described by 

Dunion (2011) is insufficiently dry to generate extensive arc clouds around African easterly 

waves (AEWs) or TCs. However, substantial arc clouds (100s of km in length and lasting for 

several hours) consistently form in the tropics in the periphery of these tropical disturbances. 

Dunion (2011) described two additional types of air masses frequently found in the tropical 

North Atlantic and Caribbean (both with 50-60% less low to mid-level moisture than the moist 

tropical sounding) that could effectively initiate the formation of large arc clouds: the Saharan 

Air Layer and mid-latitude dry air intrusions. It is hypothesized that the processes leading to the 

formation of arc cloud events can significantly impact an AEW or TC (particularly smaller, less 

developed systems). Specifically, the cool, dry air associated with the convectively-driven 

downdrafts that form arc clouds can help stabilize the middle to lower troposphere and may even 

act to stabilize the boundary layer. The arc clouds themselves may also act to disrupt the storm. 

As they race away from the convective core region, they create low-level outflow in the 

quadrant/semicircle of the AEW or TC in which they form. This outflow pattern counters the 

typical low-level inflow that is vital for TC formation and maintenance. 

Recent work looking at trajectory analyses and observations from aircraft and satellites suggest 

that there are preferred pathways for low to mid-level dry air to enter the periphery of tropical 

disturbances. These results may provide insight as to where and when a dry air intrusion may 

take place. To further study these preferred pathways, idealized simulations of a TC vortex 

embedded in easterly flow is examined on both an f-plane, a beta plane and relative to an easterly 

jet to examine the relative the impact of both beta drift and the Magnus effect on the entrainment 

of dry air into the TC. The conditions for the relative importance of these effects under differing 

horizontal and vertical shears of easterly flow expected with AEWs will be presented. 


Improvements to Statistical Intensity Forecasts 

John A. Knaff 1 , Mark DeMaria 1 , Kate Musgrave 2 , John Kaplan 3 , Christopher M. Rozoff 4 , James 

P. Kossin 5 , Christopher S. Velden 4 , 

(John.Knaff@noaa.gov) 

1 NOAA/NESDIS/STAR; 2 CIRA/CSU; 3 NOAA/HRD; 4 CIMSS/UW, 5 NOAA/NESDIS/NCDC 

Tropical cyclone intensity forecasts have improved relatively slowly over the last decade and 

statistical models still remain state-of-the-art. Recently with NOAA’s Hurricane Intensity 

Forecast Improvement Project (HFIP), great emphasis has been placed on numerical weather 

prediction models, which are fully expected to become the state-of-the-art methodology by the 

end of the the HFIP program. In the mean time, several new statistical techniques have been 

developed, existing techniques have been improved and the application of similar techinques are 

being developed for other tropical cyclone basins. Much of the recent improvements to existing 

methodologies have concentrated on improved use of satellite-based information from NOAA’s 

Geostationary Operational Environmental Satellite (GOES) and Polar Operational 

Environmental Satellite (POES) programs and data from other low earth orbiting satellite 

platforms. Funding for these efforts has come from a variaty of different programs including the 

GOES I/M Product Assurance Plan (GIMPAP), the Joint Hurricane Testbed (JHT), and the 

GOES-R Risk Reduction (GOES-R3) program. 

This presentation will detail the recent improvements to existing statistical intensity forecast 

techniques, recently developed techniques and planned future improvements. More specifically 

we will present recent improvements (and related verifications) to existing statistical techniques 

including the Statistical Hurricane Intensity Predictions Scheme (SHIPS), the Logistic Growth 

Equation Model (LGEM) and the Rapid Intensity Index (RII). This disucssion will include 

updates to the developmental datasets, new GOES-based, microwave-based and total precipitable 

water predictors and statistical methodologies as well as insight inferred from real-time 

experimental (JHT and GOES-R3 Proving Ground) versions of the RII that included lightning 

information. In addition, recently developed tools to anticipate rapid weakening (25-kt in 24 h) 

of non-landfalling tropical cyclones and extra-tropical transitions will be discussed. Here we will 

also review expected performance of a probabalistic estimate of rapid weakening and the factors 

found to be related to eminant (24-h) extratropical transition in a similar statistical framework. 

Finally, future plans to transfer these capabilities to other tropical cyclone basins will be briefly 

discussed. 



decision. 


Improvements in the Statistical Prediction of Tropical Cyclone Rapid Intensification 

Christopher M. Rozoff 1 James P. Kossin 1,2 , Christopher Velden 1 , Anthony J. Wimmers 1 , 

Margaret E. Kieper 3 , John Kaplan 4 , John A. Knaff 5 , and Mark DeMaria 5 

(chris.rozoff@ssec.wisc.edu), 

1 CIMSS/UW-Madison; 2 NOAA/NCDC; 3 Private Consultant; 4 NOAA/HRD; 

5 NOAA/NESDIS/StAR 

The National Hurricane Center currently uses a skillful probabilistic rapid intensification 

(RI) index (RII) based on linear discriminant analysis of the environmental and satellite-derived 

features from the Statistical Hurricane Prediction Scheme (SHIPS) dataset. In this presentation, 

two new probabilistic models for RI prediction, along with the benefits of using an ensemblemean 

of multiple models, will be reviewed. The remainder of the presentation will focus on the 

benefits of using structural predictors based on microwave imagery. 

Two new probabilistic RI models, one based on logistic regression and the other on a naïve 

Bayes framework, are evaluated. Both models incorporate data from the SHIPS dataset and have 

been developed for a variety of RI thresholds for both the Atlantic and eastern Pacific. Crossvalidation 

demonstrates that both models are skillful relative to climatology and that their skill is 

competitive with SHIPS-RII. Finally, a three-member ensemble-mean of the logistic, Bayesian, 

and SHIPS-RII models provides superior skill to any of the individual members. For a rapid 

intensification threshold of 25 kt per 24 h, the three-member ensemble-mean improves the Brier 

skill scores relative to the current operational SHIPS-RII by 33% in the Atlantic and 52% in the 

eastern Pacific. 

This presentation will also highlight improvements in statistical models of RI resulting 

from the incorporation of predictors derived from 37-GHz microwave imagery. These predictors 

exploit the internal structure of tropical cyclones often obscured from view in geostationary 

satellite data. Cross-validation of the logistic RI model in both the Atlantic and East Pacific 

shows that adding certain microwave-based predictors improves both the Brier skill score and 

probability of detection significantly. Plans to include predictors from 19- and 85-GHz 

microwave frequencies will also be discussed. 


Improving SHIPS Rapid Intensification (RI) Index Using 37 GHz Microwave Ring Pattern 

around the Center of Tropical Cyclones 

Haiyan Jiang 1 , Margie Kieper 2 , Tie Yuan 1 , Edward J. Zipser 3 , and John Kaplan 4 

(haiyan.jiang@fiu.edu) 

1 Department of Earth & Environment, Florida International University 

2 Private Consultant; 3 Department of Atmospheric Sciences, University of Utah 

4 NOAA/HRD 

The physical processes associated with rapid intensification (RI) of tropical cyclones (TCs) 

remain unsolved. Predicting these events is one of the most challenging aspects for TC 

forecasters. Recently, a robust ring pattern in the inner core area of TCs has been found in the 37 

GHz microwave images to be associated with RI. Margie Kieper initiated a subjective forecast 

method using the 37 GHz color product developed by the Naval Research Laboratory (NRL) to 

predict the onset of RI. She reviewed numerous microwave TC images, and found that a cyan 

color ring around the eye could be an early indicator of RI when environmental conditions are 

favorable. She tested this method in real time for the 2008 hurricane season in the Atlantic 

(ATL) and 2009-2010 hurricane seasons for both ATL and East Pacific (EPA) basins in 

conjunction with the SHIPS RI index. The result was very encouraging. So it will be optimal to 

translate this subjective forecast method into an objective one for wider forecast applications. 

However, the NRL 37color product is constructed by using 37 GHz vertically polarized 

(V37) and horizontally polarized (H37) brightness temperatures, and polarization correction 

temperature (PCT37). V37 and H37 are sensitive to sea surface (cold) and low-level clouds/rain 

(warm), while PCT37 is sensitive to convection (cold). The product implements a red/green/blue 

color composite from PCT37, H37 and V37 so that the sea surface in the color product appears 

green, deep convection appears pink, and low-level water clouds and rain appear cyan. Although 

this product provides unique qualitative information, quantitative information is sacrificed. It has 

been a mystery for the TC community what the cyan color truly represents. This hinders us from 

translating Margie Kieper’s eye-based subjective method into an objective and automatic 

prediction method. 

In this study, we discovered the mystery by determining quantitative values for the cyan 

color region in the NRL 37 GHz color product using a 12-yr Tropical Rainfall Measurement 

Mission (TRMM) tropical cyclone precipitation feature database. Based on these findings, an 

objective 37 GHz ring pattern RI index is developed by strictly following Margie Kieper’s ring 

pattern identification and forecasting methodology. Evaluation of the index has been done by 

using the TRMM Microwave Imager (TMI) observations of TCs in the ATL and EPA basins 

from 2002 to 2009. It is found that the 37 GHz ring pattern RI index is an independent predictor 

relative to the SHIPS RI index. By adding this ring pattern index to the SHIPS RI index, the skill 

score of the new combined indices can be as high as 55% for the ATL basin and 75% for the 

EPA basin for RI threshold at 25-kt intensity increase during 24 hours. 


Forecasting Rapid Intensification of Tropical Cyclones in the Western North Pacific Using 

TRMM/TMI 37 GHz Microwave Signal 

Tie Yuan 1 , Haiyan Jiang 1 , and Margaret Kieper 2 

(tyuan@fiu.edu) 

1 Department of Earth & Environment, Florida International University; 2 Private Consultant 

The prediction of rapid intensification (RI) of tropical cyclones has always been a great 

challenge in tropical weather forecasting. Compared with the progress in RI forecast in the 

Atlantic and Eastern North Pacific, there are few works in RI forecast in the Western North 

Pacific. Following Margie Kieper’s subjective forecast method using the 37 GHz color product 

developed by the Naval Research Laboratory (NRL) to predict the onset of RI, we have 

developed an automated detection method, 37 GHz ring pattern RI index, to identify the cyancolor 

ring pattern around the center of tropical cyclones from the Tropical Rainfall Measurement 

Mission (TRMM) Microwave Imager (TMI) 37 GHz observations (please see the abstract by 

Jiang et al. in the same conference). In this study, this ring pattern RI index is applied to the 12- 

yr TRMM Tropical Cyclone Precipitation Features (TCPFs) database to investigate the 

probability of improving RI forecast in the Western North Pacific. The result shows that the 

probability of detection (POD) of RI for storms reaching tropical storm intensity in the Western 

North Pacific is about 63%. Furthermore, it is found that the greater the intensity of tropical 

cyclones is, the larger the POD. The PODs are 40%, 75%, and 100% for tropical storms, 

typhoons, and super typhoons, respectively. 

Our technique uses the 37-GHz ring feature in the storm’s inner core, therefore it counts the 

effects of storm internal processes on intensity change. However, large-scale environmental 

conditions are the controlling factors of intensity change. We plan to use the environmental 

factors such as SST and wind shear to screen out those ring cases with unfavorable 

environmental conditions. The work is underway to generate environmental RI index similar to 

STIPS using the ECMWF INTERIM reanalysis data. The environmental RI index will be 

incorporated into the 37 GHz ring pattern RI index to further advance the RI forecast skill in the 

Western North Pacific. 


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Session 12 

Joint Hurricane Testbed 

Project Updates and 

Improved Products 

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2010 Update on The Joint Hurricane Testbed (JHT) 

Jiann-Gwo Jiing, Christopher Landsea and Shirley Murillo 

(Jiann-Gwo.Jiing@noaa.gov) 

Joint Hurricane Testbed 

Forecasting tools and techniques, developed by the research community were tested and 

evaluated at the National Hurricane Center (NHC) facilitated by the Joint Hurricane Testbed 

(JHT). Eleven 5 th round (FY09-11) projects were tested and evaluated during the 2010 hurricane 

season, following any necessary technique modifications or other preparations. These projects 

include upgrades to dynamical models and model components, enhancements to observed data 

and assimilation techniques, track forecasting algorithms, intensity estimation and forecasting 

algorithms. An announcement of Federal Funding Opportunity for new FY11 funding was 

released in July. Letters of Intent followed by full Proposals were submitted by Principal 

Investigators and evaluated by the JHT Steering Committee for a 6 th round of JHT projects to 

begin in August 2011. 


Enhancements to the SHIPS Rapid Intensification Index 

John Kaplan 1 , Joe Cione 1 , Mark DeMaria 2 , John Knaff 2 , Jason Dunion 3 , Jeremy Solbrig 4 , Jeffrey 

Hawkins 4 , Thomas Lee 4 , Evan Kalina 5 , Jun Zhang 3 , Jack Dostalek 6 , Paul Leighton 1 

(John.Kaplan@noaa.gov) 

1 NOAA/HRD; 2 NOAA/NESDIS; 3 CIMAS/HRD; 4 NRL; 5 CU; 6 CIRA 

Predicting the timing, magnitude, and duration of episodes of tropical cyclone rapid 

intensification (RI) remains one of the most challenging problems in tropical cyclone forecasting. 

In recent years, a statistically based rapid intensification index (RII) that uses predictors from the 

SHIPS model to estimate the probability of RI has been developed for operational use by 

forecasters at the National Hurricane Center (NHC) for systems in the Atlantic and eastern North 

Pacific basins. Although the operational RII forecasts exhibited some skill in each of the 

aforementioned basins when validated for the recent 2008 and 2009 Hurricane seasons, the skill 

of the RII was relatively low in the Atlantic basin and only in the low to moderate range in the 

eastern North Pacific basin. Thus with support from the NOAA Joint Hurricane Testbed (JHT), 

research is currently being conducted to improve the operational RII by including predictors 

derived from three new sources of inner-core information. The first of these three new sources is 

the time evolution of the structure of the inner-core as deduced using standard principlecomponent 

analysis of GOES infra-red (IR) imagery while the second is microwave-derived total 

precipitable water. The final source is lower tropospheric GFS model temperature and moisture 

data and sea-surface temperature estimates derived from an inner-core sea-surface temperaturecooling 

algorithm. 

In year 1 of this JHT proposal, an experimental version of the SHIPS rapid intensification 

index (RII) was developed for the Atlantic basin utilizing predictors from these three new 

information sources. This new experimental version of the Atlantic RII was tested in real-time 

during the latter part of the 2010 Atlantic Hurricane Season for the first time. A verification of 

these real-time forecasts as well as those that were obtained by re-running cases that occurred 

prior to the commencement of these tests using real-time GFS data and operational NHC track 

forecasts will be shown. More recently, an experimental version of the RII was also developed 

for the eastern North Pacific basin using predictors that were quite similar to those that were used 

to derive the experimental Atlantic version. The results of these efforts will also be presented at 

the conference. 


Status and plans for the development of a unified dropsonde 

quality assurance and visualization capability, ASPENV3 

Michael L. Black 1 , Charles L. Martin 2 , 

Paul Flaherty 3 , Jackie Almeida 3 , Joseph E. Latham 4 

(Michael.Black@noaa.gov) 

1 NOAA/AOML/HRD; 2 Earth Observing Laboratory, NCAR; 

3 Aircraft Operations Center, MacDill AFB; 4 53 rd Weather Reconnaissance Squadron, 

In 2009 and 2010, the Joint Hurricane Testbed (JHT) funded a joint NOAA and NCAR project to 

develop a revised software package to perform real-time quality control (QC) of dropsonde 

observations from AFRC and NOAA aircraft. The primary goal of the project is to provide a 

more robust editing and visualization capability than is currently available to ensure that realtime 

observational and research data from dropsonde observations are of the highest quality and 

as error-free as possible. The software package combines the graphics capability and ease of use 

of NCAR’s current ASPEN software with some of the additional editing capabilities and refined 

QC algorithms contained in NOAA’s Editsonde software. The new software suite operates on 

multiple computer platforms, incorporates publicly available graphics frameworks, and will be 

configurable to run in either a real-time, basic mode or in an enhanced mode for post analyses of 

the dropsonde data. 

An initial prototype software package, ASPENV3, has been completed, will run in Windows, 

Mac OSX, or Linux computer operating systems, and is available for testing by experienced 

users. Additional components are currently being added and an official release of the software is 

expected to occur prior to the start of the 2011 hurricane season. A progress report on the stage 

of development and plans for testing and refining the software will be given. A demonstration of 

ASPENV3 will be presented and some of the new capabilities will be briefly discussed. 


Advanced Applications of Monte Carlo Wind Probability Model: 

A Year 2 Joint Hurricane Testbed Project Update 

Mark DeMaria 1 , Robert DeMaria 2 , Andrea Schumacher 2 , Daniel Brown 3 , 

Michael Brennan 3 , Richard Knabb 4 , Pablo Santos 5 , David Sharp 6 , John Knaff 1 and Stan Kidder 2 

(Mark.DeMaria@noaa.gov) 

1 NOAA/NESDIS; 2 CIRA, Colorado State University; 3 NOAA/NCEP/NHC; 

4 The Weather Channel; 5 NOAA/National Weather Service, Miami, FL; 

6 NOAA/National Weather Service, Melbourne, FL 

Under previous JHT support, a program for estimating the probability of occurrence of 34, 50, 

and 64 kt winds was developed by NESDIS and CIRA. A Monte Carlo (MC) method was 

utilized to combine the uncertainty in the track, intensity, and wind structure forecasts for 

tropical cyclones. The MC probability program was transitioned to NHC operations in 2006. 

In the current project, four new applications of the MC model were proposed including (1) 

Landfall timing and intensity distributions; (2) Methods for using the MC model to enhance 

WFO local products; (3) Probabilities integrated over coastal segments; (4) Automated guidance 

for issuing coastal watches and warnings. A prototype graphical user interface has been 

developed for items (1), (3), and (4) above, and examples will be presented. A validation of the 

MC model for a large sample of cases for coastal and inland points was completed to help define 

probability thresholds needed for the WFO local application per item (2). Results from that study 

were presented last year, and will be very briefly summarized. 

Four refinements to the MC model code were also proposed. These include (1) A procedure to 

adjust the model time step for fast moving and small storms; (2) Modification of the azimuthal 

interpolation routine that occasionally leads to inconsistent probability values for 34, 50, and 64 

kt winds; (3) Evaluation of the spatial interpolation method that sometimes results in 

inconsistencies between the gridded and text probabilities; (4) Evaluation of the underlying wind 

radii model utilized by the MC model. Results from items (1) and (4) were presented last year, so 

the emphasis will be on results from (2) and (3). 



decision. 


A New Secondary Eyewall Formation Index; Transition to Operations and Quantification 

of Associated Hurricane Intensity and Structure Changes 

A Joint Hurricane Testbed Project (Year 2) 

Jim Kossin 1,2 , Matt Sitkowski 2,3 , and Chris Rozoff 2 

(james.kossin@noaa.gov) 

1 NOAA/NCDC, Asheville, NC; 2 Cooperative Institute for Meteorological Satellite Studies 

(CIMSS), University of Wisconsin; 3 Department of Atmospheric and Oceanic Sciences, 

University of Wisconsin 

Eyewall replacement cycles in hurricanes are generally associated with rapid and dramatic 

changes in wind structure and intensity. While the intensity fluctuations are usually transient and 

of particular concern when storms are near land, the broadening of the wind-field tends to be a 

long-lived change that has substantial impacts on shipping and marine interests because of the 

associated increases in wave height, storm surge, and radius of 50 kt wind (R50). In fact, eyewall 

replacement cycles represent a highly efficient (and easily identifiable) pathway to storm growth. 

Despite the implications and known impacts of eyewall replacement cycles, objective tools to 

forecast these events were not available prior to the 2010 hurricane season. Consequently, 

forecasters have relied on subjective methods for estimating the onset of these events and 

adjusting intensity forecasts accordingly. 

In Year-1 of this Joint Hurricane Testbed project we transitioned a new objective model into 

operations at the National Hurricane Center, and the model was run in a real-time experimental 

mode during the 2010 season. The model provides probability of onset of an eyewall 

replacement cycle out to 48 hours based on observed and forecast environmental features and 

observed storm features (as measured with GOES infrared imagers). In the first part of this 

presentation, we will verify the model performance and skill for the 2010 season. 

In the ongoing Year-2 of this project, we are constructing and documenting the first general 

climatology of intensity and structure changes associated with eyewall replacement cycles. This 

climatology is based on low-level aircraft reconnaissance data and is being utilized to construct 

additional objective forecast tools. These tools will provide prognostic information about the 

most likely intensity evolution based on measured environmental and storm features with the 

primary goal of reducing intensity forecast error. Recent results of this part of the project will be 

introduced in the second part of this presentation. 


ATCF Requirements, Intensity Consensus and Sea Heights Consistent with NHC Forecasts 

(Year 2) 

Charles R. Sampson 1 , Ann Schrader 1 , Efren Serra 1 , Paul Wittmann 2 , Hendrik Tolman 3 , Chris 

Sisko 4 , Chris Lauer 4 , Jessica Schauer 4 , John Knaff 5 , Mark DeMaria 5 , Andrea Schumacher 5 

(sampson@nrlmry.navy.mil) 

1 NRL; 2 FNMOC; 3 NOAA/NCEP; 4 NHC; 5 CIRA 

The Automated Tropical Cyclone Forecasting System (ATCF) is one of the core forecast 

systems at U.S. tropical cyclone forecast centers and has now been in operations at the NHC for 

twenty years. Modifications to the ATCF are relatively inexpensive, making it a preferred target 

platform for Joint Hurricane Testbed and Hurricane Forecast Improvement Project (HFIP) 

products and algorithms. This talk reviews progress in the second and final year of this ATCFfocused 

JHT project. The three parts of this project are to: 1) Address NHC User Requirements, 

2) perform studies with intensity consensus aids, and 3) to run real-time, evaluate and possibly 

implement an algorithm to produce sea heights consistent with NHC forecasts. This JHT project 

is on schedule. Additional funding for improvements to the ATCF in 2011 and beyond comes 

courtesy of HFIP. 

The views, opinions, and findings contained in this report are those of the authors and should not 

be construed as an official National Oceanic and Atmospheric Administration or U.S. 

government position, policy, or decision. 


Atlantic Warm Pool SST Bias in HYCOM 

Chunzai Wang 1 and Sang-Ki Lee 1,2 

(Chunzai.Wang@noaa.gov) 

1 NOAA/AOML; 2 CIMAS/University of Miami 

The rationale for this study is the recent scientific finding that the Atlantic warm pool (AWP) 

- a large body of warm water comprised of the Gulf of Mexico, the Caribbean Sea, and the 

western tropical North Atlantic - may add a value to improving the simulation of Atlantic 

tropical cyclone (TC) in operational hurricane forecast models. In particular, recent studies using 

both observations and models have shown that a large AWP reduces the vertical wind shear and 

increases the convective available potential energy over the main development region for 

Atlantic hurricanes, and thus facilitates the formation and development of Atlantic TCs. 

Therefore, our ultimate goal is to improve the forecast of the formation and intensification of 

Atlantic hurricanes in NCEP/EMC operational models, by improving the simulations of the 

AWP in that model during the Atlantic hurricane season of June to November. 

In order to evaluate the simulation of the AWP in HYCOM, which is the ocean model 

component of the NCEP/EMC operational models, we have setup HYCOM for the Atlantic 

domain between 20 o S and 70 o N using RTOFS-Atlantic, the NCEP/EMC operational ocean 

model, as the basic platform. The HYCOM is thermally coupled to an Atmospheric Mixed layer 

Model (AML) to allow physically more realistic thermal interactions at the air-sea interface, thus 

to minimize thermodynamic inconsistency at the air-sea interface. Our major finding is that the 

HYCOM tends to create a large cold bias in the AWP region due to its inherent oceanic heat flux 

errors. Although the overall time evolution of the AWP bias is quite slow, a large cold SST bias 

with persistent spatial structure may emerge during a 5-day forecast, during which the RTOFS is 

not initialized. An important implication is that, since the RTOFS is used to initialize the 

NCEP/EMC operational hurricane forecast model, the cold AWP SST bias can be introduced to 

the hurricane forecast model and thus negatively affect the hurricane forecast. 


Tools for Coordinating Aircraft During Hurricane Field Campaigns 

Rich Blakeslee 1 , Michael Goodman 1 , John Hall 2 , Matt He 2 , Paul Meyer 1 , Michelle Garrett 2 , 

Kathryn Regner 2 , Helen Conover 2 , Tammy Smith 2 

(richard.blakeslee@nasa.gov) 

1 National Aeronautics and Space Administration; 2 University of Alabama in Huntsville 

The NASA Real Time Mission Monitor (RTMM) is a situational awareness decision-support 

tool that integrates real time aircraft tracks, waypoints, satellite imagery, radar products, surface 

observations, model output parameters and airborne remote sensing variables in an easy to use 

and view web-based application. RTMM enables real time decision-making for mission 

scientists, pilots, mission managers, instrument scientists and program managers by providing 

up-to-date information about the weather, spacecraft, and the location, altitude and heading of 

the aircraft. 

The Real Time Mission Monitor optimizes both airborne science experimental field campaigns 

and operational science aircraft missions. The second-generation version of RTMM is now fully 

integrated into a web browser portal and no longer relies on the standalone Google Earth 

application. The implementation in a web browser makes it easy for any authorized user 

anywhere with an Internet connection to follow and coordinate aircraft tracking during dynamic 

hurricane aircraft missions. 

The Real Time Mission Monitor is a proven tool having been used in many field experiments 

from arctic forest fire missions to soil moisture mapping as well as tracking the BP Gulf Oil spill. 

In the summer of 2010, RTMM was integral to the success of the PREDICT, GRIP, and IFEX 

coordinated manned and unmanned hurricane flights. An overview of the use of RTMM during 

the 2010 hurricane flights, its planned usage in 2011 and potential future manned and unmanned 

aircraft flights will be described. RTMM animations of the 2010 hurricane flights and 

demonstrations of RTMM and the pre-flight waypoint planning tool will be provided. 


P 

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Poster Session 

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Real-time radar processing in the 2010 Hurricane Season and plans for 2011 

John F. Gamache 

(John.Gamache@noaa.gov) 

NOAA/AOML/Hurricane Research Division 

During the 2010 Hurricane Season there were milestones achieved concerning the NOAA WP- 

3D airborne tail Doppler radar (TDR) and its use to help initialize the Hurricane Weather 

Research and Forecasting Model (HWRF). One milestone was the use of the data in the 

experimental version of the HWRF model a number of times during the season. Another was the 

first assimilation of data in a parallel run of the operational HWRF during Hurricane Tomas. To 

accomplish the latter assimilation, several organizations worked to complete the construction and 

test the operation of the data pipeline from the P3 TDR, consisting of the processing, 

compression, and transmission of the quality-controlled Doppler-radial velocity data via the 

Aircraft Operations Center (AOC) to NCEP Central Operations (NCO). We will report briefly 

on the nature of this pipeline, and the success and problems encountered during the season in 

processing Doppler data in real time. We will also discuss the future plans for the radar as the P3 

radar processing system is changed from an older Sigmet RVP-5 system to the RVP-8 system. 

Poster Session – Page 1

Real-time Transmission of NOAA Tail Doppler Radar Data 

J Carswell 1 , P. Chang 2 , M. Mainelli 3 and J. Hill 4 


1 Remote Sensing Solutions, 2 NOAA/NESDIS/STAR, 3 NOAA NCEP, 4 NOAA AOC 

The NOAA WP-3D aircraft provide X-band Doppler/reflectivity measurements of tropical 

storms and cyclones. Doppler measurements from volume backscatter precipitation profiles can 

provide critical observations of the horizontal winds as the precipitation advects with these 

winds. In 2010, NOAA NESDIS, NOAA AOC and Remote Sensing Solutions teamed to capture 

these profiles and send the radial Doppler profile observations to National Weather Service in 

near real-time over satellite communication data link. The design of this transmission system 

included features to enhance the reliability and robustness of the data flow from the P-3 aircraft 

to the end user. The end objective is to provide these Doppler profiles in a routine fashion to 

NWS and others in the forecasting community for operational utilization in support of hurricane 

forecasting and warning. 

In this paper we present an overview of this work, accomplishments that were achieved in 2010 

and discuss plans for 2011 hurricane season. 


Improved Hurricane-force Surface Winds and Rain Rate Retrievals 

with the Step Frequency Microwave Radiometer 

J Carswell 1 , P. Chang 2 , Z. Jelenak 2 and S. Frasier 3 


1 Remote Sensing Solutions, 2 NOAA/NESDIS/STAR, 3 University of Massachusetts 

With the operational deployment of the Stepped Frequency Microwave Radiometer (SFMR), 

hurricane reconnaissance and research aircraft provide near real-time observations of the 10-m 

ocean surface wind speed both within and around tropical storms and cyclones. These data are 

used by hurricane specialists to assist in determining wind radii and maximum sustained winds - 

critical parameters for determining and issuing watches and warnings. These observations are 

also used for post storm analysis, model validation, and even ground truth for future satellitebased 

wind sensors. It is therefore imperative that any errors in these observations be understood 

and reduced as much as possible. 

In previous studies, SFMR rain retrievals have been shown to exhibit a bias of 5 mm/hr and to 

under report the rain rate, suggesting that the SFMR rain absorption model requires 

improvement. To address this, we present further studies documenting the problem, as well as a 

new rain absorption model. Using this new model in the SFMR retrieval process, significant 

improvements in both the wind speed and rain rate retrievals are achieved. 


Collocated ASOS and WSR-88D Depict Collapsing Core and Maximum Wind Gust at 

Melbourne FL in the Eyewall of Hurricane Erin (1995) 

Keith G. Blackwell 

(kblackwell@usouthal.edu) 

Coastal Weather Research Center and 

Center for Hurricane Intensity and Landfalls Investigations (CHILI) 

Department of Earth Sciences, University of South Alabama 

Landfalling tropical cyclones often contain collapsing cores of heavy precipitation within their 

eyewalls. Several studies indicate the likely linkage between downburst-like features and strong 

wind gusts in hurricane eyewalls; however, very few surface-based measurements of winds 

associated with these features actually exist. In these studies, National Weather Service WSR- 

88D Archive Level II data were analyzed in search of elevated reflectivity regions exceeding 50 

dBZ and then temporally examined for signs of vertical collapse, in some cases near or over 

surface wind observation sites. 

Holmes et al. (2006) presented an introductory glimpse into collapsing precipitation cores in 

hurricanes Ivan and Katrina; however no surface wind measurements were available in those 

areas to verify the actual strength of the wind within those features. Blackwell and Medlin 

(2008) produced a radar climatology of collapsing core frequency within all U.S. landfalling 

hurricane eyewalls between 1994 and 2007. This climatological study found that some storms 

were almost completely void of heavy eyewall convection and collapsing cores, whereby others 

contained extremely prolific activity. One of the most prolific collapsing core producers was 

Hurricane Danny (1997) in Mobile Bay, AL. Blackwell (2009) presented an example of a 

possible collapsing core within Danny’s eyewall which produced a wind gust of 45 m s -1 (101 

mph) at the C-MAN station on Dauphin Island, AL. Blackwell et al. (2010) detailed another 

collapsing core event in a spiral band of Hurricane Katrina which produced a reported wind gust 

to 122 mph on a docked ship and significant damage along the Mobile AL waterfront. 

In each of the above studies, surface wind measurements were sparse or nonexistent and none 

were collocated with the radar location; thus, near-surface radar information was not available 

near the surface observation. The current study depicts a collapsing core eyewall event in which 

the radar and wind observation sites are collocated, providing low-level radar detail. Melbourne, 

FL (KMLB) experienced the northeastern eyewall of landfalling category 1 Hurricane Erin 

(1995) in the predawn hours of 2 August 1995. A large convective core of >50 dBZ reflectivity 

experienced a collapse from above 3000 m (~10,000 ft) to the surface as it approached and swept 

across the ASOS station. A hurricane-force wind gust of 34 m s -1 (76 mph) occurred with the 

passage of this feature, representing the highest wind measured at that location during the storm. 

The adjacent WSR-88D clearly shows the descending reflectivity core and acceleration of the 

near-surface winds as the feature approaches. The collocation of Doppler radar and surface wind 

measurements make this a unique and interesting event for study and clearly links a collapsing 

core with a strong hurricane wind gust. Details will be shown at the conference. 


Wide Swath Radar Altimeter (WSRA) Wave Spectra from Hurricane Ike compared with 

WaveWatch III 



1 ProSensing; 2 NOAA/ESRL/PSD 

The WSRA was first deployed aboard the NOAA WP-3D hurricane reconnaissance 

aircraft during the 2008 hurricane season. Raw data gathered during several hurricane 

reconnaissance flights was processed into directional ocean wave spectra, demonstrating the 

basic functionality of the WSRA. During the flight into Hurricane Ike on September 11, 

sufficient data were collected to provide an overview of the wave field variation throughout the 

all regions of the storm. 

These WSRA-obtained wave field spectra are compared with the WaveWatch III (WW3) 

numerical wave model. The WW3 results were provided by Isaac Ginis and Brandon Reichl of 

the University of Rhode Island. The WW3 wave field spectra were calculated for the time 1230 

UTC on September 11, which is the midpoint of the 5-hour WSRA raw data acquisition period. 

There is generally a good agreement between the WSRA observations and the WW3 predictions 

of the spatial variation of wave height around the hurricane. The poster will show segments of 

WSRA wave topography throughout Hurricane Ike, as well as detailed comparisons of the 

resulting directional wave spectra with the WW3 model predictions. 


Storm Surge Measurement Potential of the Wide Swath Radar Altimeter 



1 ProSensing; 2 NOAA/ESRL/PSD 

The Wide Swath Radar Altimeter (WSRA) has the potential to provide operational, targeted 

measurements of storm surge for land-falling hurricanes. The concept of airborne measurement 

of storm surge consists of subtracting the absolute altitude of the aircraft determined using the 

Global Positioning System (GPS) from the WSRA-measured distance to the sea surface. The 

result of that simple calculation is the absolute elevation of the water for the particular point in 

time and space. Wright, et al. (2009) demonstrated the technique in a research mode using the 

NASA Scanning Radar Altimeter (SRA) which has since been decommissioned. 

The absolute range calibration of the WSRA can be determined and maintained during the flights 

using tide gauges within Tampa Bay when returning from each operation, as well as flying by 

tide gauges in the vicinity of the landfall. The poster examines the range accuracy of the WSRA 

and demonstrates the absolute calibration technique using a data segment over Tampa Bay when 

N42RF was returning from a flight into Hurricane Ike on September, 11 2008. Historical SRA 

data are used to demonstrate the potential benefits of targeted storm surge measurements. 


Direct Interpretation of COSMIC Refractivity Data in the Tropical Cyclone Environment 

Christopher M. Hill, Patrick J. Fitzpatrick, and Yee Lau 

(hillcm@gri.msstate.edu) 

Geosystems Research Institute, Mississippi State University, Stennis Space Center, MS 

This study continues to explore the utility of the Constellation Observing System for 

Meteorology, Ionosphere, and Climate (COSMIC) in measuring moisture in the vicinity of 

tropical cyclones. From a formula relating GPS signal refractivity to temperature, pressure, and 

vapor pressure (Smith and Weintraub 1953, Kursinski et al. 1995), especially high (low) values 

of refractivity at a known pressure level correspond to high (low) vapor pressure in a relatively 

high temperature environment. The implication is that a relative measure of moisture can be 

attained with only refractivity at a known pressure level, and without specific knowledge of 

temperature, in a tropical environment. The relation of refractivity to tropospheric 

thermodynamics further yields a critical value of refractivity below which water vapor saturation 

– and therefore clouds – cannot exist at a known pressure level. 

The above findings are applied in the evaluation of a June-September climatology of COSMIC 

refractivity over the tropical and subtropical eastern Atlantic Ocean, as well as in the evaluation 

of individual COSMIC refractivity profiles with varying proximity to select Atlantic tropical 

cyclones. Nomograms relating refractivity to pressure and temperature have been constructed to 

assist in the determination of moisture content for given values of refractivity and pressure. 

References: 

Kursinski, E. R., G. A. Hajj, K. R. Hardy, L. J. Romans, and J. T. Schofield, 1995: Observing 

tropospheric water vapor by radio occultation using the Global Positioning System, Geophys. 

Res. Lett., 22, 2365–2368, doi:10.1029/95GL02127. 

Smith, E. K., and S. Weintraub, 1953: The constants in the equation for atmospheric refractivity 

index at radio frequencies. Journal of Research of the National Bureau of Standards, Vol. 50, p. 

39-41. 


Ocean’s Impact on the Intensity of Three Recent Typhoons (Fanapi, Malakas, and Megi) – 

Results from the ITOP Field Experiment 

I-I Lin 1 and Peter G. Black 

( peter.black.ctr@nrlmry.navy.mil) 

1 Department of Atmospheric Sciences, National Taiwan University, Taipei, Taiwan; 

2 Naval Research Laboratory, Monterey, USA 

2 

During the 20 August to 20 October 2010 ITOP field experiment, three typhoon cases, 

Fanapi, Malakas, and Megi were studied. Using airborne C130 dropwindsonde data, C130 

AXBT (Airborne Expendable Bathythermograph) data, in situ upper ocean thermal structure data 

from the Argo floats, satellite sea surface temperature and altimetry data together with an ocean 

mixed layer model, the impact of ocean’s thermal structure to the intensity of these 3 typhoons 

are investigated. It is found that all three typhoons passed over regions of similarly warm sea 

surface temperature (SST) of ~ 29.5 ˚ C. However, much distinction is found in the subsurface. 

Category-2 Typhoon Malakas passed over region of the shallowest subsurface warm layer, as 

characterised by the depth of the 26 ˚ C isotherm (D26) of about 37 -40m and Upper Ocean Heat 

Content (UOHC) of ~ 38-44 kj/cm 2 . Category-3 typhoon Fanapi passed over region of moderate 

subsurface warm layer, with D26 of ~ 60-70m and UOHC of ~ 65-78 kj/cm 2 . Category-5 

typhoon Megi passed over region of the deepest subsurface warm layer, with D26 reaching 124- 

132m and UOHC reaching 136-138 kj/cm 2 . It is found that this distinction in the subsurface 

thermal structure played critical role in the intensification of the three typhoon cases. Due to the 

very deep D26 and high UOHC, very little typhoon-induced ocean cooling negative feedback 

(typically < 1˚ C) for Megi was found. This very minimal negative feedback enabled ample air - 

sea enthalpy flux supply to support Megi’s intensification. Based on the preliminary report from 

the Joint Typhoon Warning Center (JTWC), Megi’s peak intensity reached 160kts, a very high 

intensity not often observed even for category-5 typhoons. In contrast, though with very warm 

pre-typhoon SST of ~ 29.5 ˚ C, the subsurface ocean condition for Malakas and Fanapi was 

much less favourable. As a result, the subsurface cold water could be much easily entrained and 

upwelled to the surface to limit the intensification for Malakas and Fanapi. Finally, it was found 

that the very deep subsurface warm layer and high heat content over the region where Megi 

passed was about 10-30% higher than the climatological values. Preliminary results suggest the 

possible contribution of the La Nina event in causing such warm anomaly over the western North 

Pacific in October 2010. 


Coupled Air-Sea Observations in Tropical Cyclones during ITOP/TCS10 

Chiaying Lee and Shuyi S. Chen 


The effects of the atmosphere-ocean coupling on tropical cyclone (TC) intensity have been 

studied in numerical models with limited air-sea observations. One of the most challenging 

problems in TC intensity forecasting is the lack of quantitative measure of the impact of air-sea 

coupling process on TC structure and intensity change. Observations from ITOP/TCS10 

provided a comprehensive data set in TCs with co-located atmospheric and oceanic 

measurements across the air-sea interface. One of the main objectives of ITOP10/TCS-10 is to 

measure air-sea fluxes as well as the boundary layer structure using co-located dropsondes and 

AXBTs. In this study we compare the coupled WRF (CWRF) model simulations of typhoons 

over the West Pacific with the ITOP/TCS10 observations to examine the presence of asymmetry 

in surface enthalpy fluxes over the storm-induced cold wake region, which causes a relatively 

shallow and stable boundary layer. A trajectory and tracer analysis in CWRF indicated that the 

stable boundary layer results in less depletion of energy from inflow to convection, and therefore 

such boundary layer asymmetry has energetic influence on TC intensity and convective 

structure. By analyzing the dropsondes and AXBTs data from ITOP10/TCS10, we aim to 

evaluate/validate coupled model forecasts and further test the effects of air-sea coupling 

processes on TC structure and intensity forecasts. 


Coming soon: AMSU in GEO 

Bjorn Lambrigtsen 

(lambrigtsen@jpl.nasa.gov) 

Jet Propulsion Laboratory, California Institute of Technology 

As a result of NASA’s multi-million dollar investments in the development of the Geostationary 

Synthetic Thinned Array Radiometer (GeoSTAR) at the Jet Propulsion Laboratory (JPL), the 

technology required to build a geostationary microwave sounder – “AMSU in GEO” – is now 

sufficiently mature that a space mission can be initiated. A JPL-led effort is under way to 

develop a low-cost GeoSTAR mission under the new NASA “Ventures” program in partnership 

with NOAA and European colalborators. If a Ventures proposal is successful, the development 

could start in 2012, and launch as a hosted payload would take place in the 2016-2018 time 

frame. The exact timing depends on the availability of hosting oppurtunities. This mission will 

be focused on storms in the North Atlantic: hurricanes during the summer and mid-latitude 

storms the rest of the year. With data products ranging from AMSU-equivalent brightness 

temperatures to derived temperature, water vapor and reflectivity profiles, it will be possible to 

monitor the intensity and structure of storms continuously. Hurricane applications range from 

real-time detection of rapid intensification to accurate estimates of vortex location and the 

structure of the inner core for enhanced forecast initialization, and this mission can contribute 

significantly to the Hurricane Forecast Improvement Project (HFIP). General numerical weather 

prediction is also expected to benefit from this mission, particularly from precipitation and 

height-registered wind-vector products. We discuss the status of the GeoSTAR development, 

plans for a Ventures mission, and opportunities to participate. 

Copyright 2011 California Institute of Technology. Government sponsorship acknowledged. 


Assimilating COSMIC GPS RO data for Investigating TC 

Genesis in the Eastern Atlantic Region 

Keren Rosado and Sen Chiao 

Marine and Environmental Systems 

Florida Institute of Technology 

This study is aimed to investigate the impact of using Global Positioning System Radio 

Occultation (GPS RO) sounding data (i.e., Constellation Observing System for Meteorology, 

Ionosphere and Climate; COSMIC) for tropical cyclogenesis research. The Weather Research 

and Forecasting (WRF-ARW) model and the WRF data assimilation system (i.e., WRF 3DVAR) 

are employed to simulate tropical depression- 8 (i.e., TD-8) of 2006 when the African Easterly 

Wave (AEW) and vortex moved out over the Eastern Atlantic (12.5°N–18°W). A noteworthy 

feature was that Saharan dust outbreak was also observed during this period, which made this 

case more sophisticated. The time frame to be focused is from 1200 UTC 09 to 1200 UTC 12 

UTC 12, August 2006. The level 2 wetPrf COSMIC data is adopted in this research. A 72-hr 

integration is performed in order to better simulate the evolution of TD-8. The initial and time 

dependent lateral boundary conditions are derived from the NCEP final analysis (FNL) data. A 

3-domain nested simulation is configured with 30-km, 10-km and 3.3-km horizontal resolutions, 

respectively. The simulation results are evaluated using the African Monsoon Multidisciplinary 

Analysis (AMMA) field experiment as well as NASA TRMM MERG products. Statistical 

analyses (e.g., bias, absolute mean error, root mean square errors and correlation coefficients) are 

performed for quantitative comparisons. It is anticipated that the outcome from this research may 

further advance our understanding of the role Saharan Air layer (SAL) in association with 

tropical cyclogenesis. 


Sensitivities of air-ocean-wave coupling on the prediction of Hurricanes Frances and Ivan 

Sue Chen 1 , Travis Smith 2 , Saša Gaberšek 1 , Tim Campbell 2 , Shouping Wang 1 , James Doyle 1 , and 

Rick Allard 2 

1 Marine Science Division, Monterey 

2 Oceanography Division, Stennis 


A series of model runs were conducted to exam the sensitivities of air-ocean-wave coupling on 

the intensity and structure change of hurricanes Frances and Ivan as well as the associated ocean 

and wave response. The hurricane model used for this study is the newly developed six-way airocean-wave 

fully coupled COAMPS-TC. The coupling is achieved using the Earth System 

Modeling Framework to couple the COAMPS-TC with the Navy Coastal Ocean Model (NCOM) 

and Simulating WAves Nearshore (SWAN). Special in situ measurements of atmosphere, ocean, 

and wave during the Coupled Boundary Layer Air-Sea Transfer Experiment (CBLAS) field 

campaign sponsored by the Office of Naval Research were used to validate the model results. 

For the simulations of Hurricane Frances, it is found using a higher resolution ocean grid 

improved the magnitude of the trailing cold sea surface temperature anomaly forced by the 

hurricane. The forecast sea temperature bias below the ocean mixed layer was further reduced 

when the high-resolution ocean model initial condition was improved using the ocean data 

assimilation in the ocean spin-up period. In addition, the significant wave height bias was 

reduced if using the level-off wind stress value from CBLAS instead of the original generation 3 

wind source term in SWAN. Including the wave feedback to the atmosphere also produced a 

much higher value of momentum drag near the eyewall region. The overall intensity and track 

forecast differences between the uncoupled and various coupled runs (one to six-way coupling) 

were found to be as large as 18 m/s and 10 nautical miles, respectively. 

For the hurricane Ivan study, a special ADCP data array collected by NRL is also used to 

evaluate the shallow and deep water current response. Including the wave Stokes’s drift, wave 

radiation stress, and wave bottom stress feedback improved the complex correlation coefficients 

and mean directional error for the ocean current. The wave spectrum comparison between 

SWAN and Scanning Radar Altimeter showed SWAN generated too much energy in long waves 

which in turns produced a larger significant wave height bias. These preliminary results indicate 

a more consistent treatment of momentum stress, sensible heat flux, and latent heat flux at the 

air-sea interface may be needed in order to improve the forecast of the hurricane environment. 

The development of a new unified air-sea interface module jointly with NOAA, University of 

Miami, and University of Rhode Island founded by National Oceanographic Partnership Program 

is discussed. 


Developing an Atlantic Ocean initialization based on the Navy Coupled Ocean Data 

Assimilation (NCODA) product for the operational GFDL and GFDN hurricane models 

Richard Yablonsky, Isaac Ginis, Seunghyon Lee, and Biju Thomas 

(ryablonsky@gso.uri.edu) 

Graduate School of Oceanography, University of Rhode Island 

Currently, NOAA’s operational GFDL hurricane model and the U.S. Navy’s operational GFDN 

hurricane model use a feature-based modeling technique along with the U.S. Navy’s Global Data 

Environmental Model (GDEM) monthly climatology for ocean initialization in the western 

North Atlantic basin. In other worldwide ocean basins, the GFDN hurricane model uses the 

Navy Coupled Ocean Data Assimilation (NCODA) daily product for ocean initialization. Here, 

we will discuss the development an NCODA-based ocean initialization for the western North 

Atlantic basin and evaluate its performance against the feature-based/GDEM initialization with 

the ultimate goal of determining whether or not it is advantageous to replace the featurebased/GDEM 

initialization with the NCODA-based initialization in the Atlantic basin in the 

GFDL and/or GFDN hurricane models. 


Spatial Verification of Tropical Cyclone Model Track and Intensity Forecasts 

Timothy Marchok 1 and Arielle Alpert 2 

(timothy.marchok@noaa.gov) 

1 NOAA / GFDL; 2 Johns Hopkins University 

One component that is critical to the development of tropical cyclone modeling is the evaluation 

and verification of model forecasts. Models that perform well for track forecasting may or may 

not perform well for intensity forecasting, and vice versa. Likewise, a model that performs well 

in one ocean basin may have difficulty in another. In addition, even within a given ocean basin, 

there may be subregions within that basin where a model may exhibit better track or intensity 

forecasting skill. In this poster, we examine the spatial variability of track and intensity forecast 

performance within the Atlantic Basin for forecasts from various operational regional and global 

models for the 2006-2009 hurricane seasons. 

We present results for several different types of analyses. Due to the varying density of forecast 

track points across the basin, we performed Barnes analyses for model errors and biases in order 

to spatially smooth the data. Spatial error plots derived from these analyses are shown which 

may be used for a qualitative overview, highlighting key areas of error among models. In 

addition, quantitative analyses are also included that detail track and intensity forecast 

performance over four subregions within the Atlantic Basin. Finally, we present results from an 

outlier analysis that determines, for each model, the geographic locations of two-, three- and 

four-sigma track and intensity forecast errors. Results from these analyses may help forecasters 

and model developers alike to better understand some of the biases that exist in the various 

models. 


Improving Ocean Model Performance in Coupled Hurricane Forecasts through Improved 

Initialization 

George R. Halliwell 1 , Lynn K. Shay 2 , Debra Willey 3 , Jodi Brewster 2 , Benjamin Jaimes 2 , Gustavo 

Goni 1 

(George.Halliwell@noaa.gov) 

1 Physical Oceanography Division, NOAA, Atlantic Oceanographic and Meteorological 

Laboratory 

2 Division of Meteorology and Physical Oceanography, RSMAS, University of Miami 

3 Cooperative Institute of Marine and Atmospheric Studies, University of Miami 

4 NOAA, Atlantic Oceanographic and Meteorological Laboratory 

The goal of the Shay-Halliwell JHT project is to improve the performance of ocean models 

for coupled hurricane forecasting. This goal will be achieved by improving the accuracy of ocean 

model initialization and improving ocean model physics and numerics. Based on our prior work, 

forecast SST depends so strongly on initialization accuracy that evaluation of ocean model 

upgrades cannot be reliably performed until significant initialization improvements are made. 

Candidate products that can be used to initialize ocean models include several real-time dataassimilative 

ocean analyses along with synthetic upper-ocean temperature-salinity analyses 

derived from satellite observations (altimetry and SST). Unfortunately, evaluation and 

identification of optimum initialization products has been hindered by the relative lack of threedimensional 

synoptic observations of the ocean in comparison to the atmosphere. 

An unprecedented set of ocean observations was collected in the eastern Gulf of Mexico 

during spring and summer 2010 in response to the Deepwater Horizon oil spill. Nine synoptic 

surveys from a NOAA P-3 hurricane research aircraft were conducted by NOAA and 

UM/RSMAS between 8 May and 9 July, deploying AXBTs, AXCTDs, and AXCPs. 

NOAA/AOML and other institutions conducted extensive in-situ surveys of upper-ocean 

temperature, salinity, and currents on cruises. NOAA/AOML produced satellite-derived products 

(e.g. SST, SSH, surface currents) and also deployed surface drifters to provide surface 

measurements and track Lagrangian trajectories. An extensive set of moored observations was 

collected by the Minerals Management Service. This unprecedented regional dataset will enable 

a high-quality evaluation of potential ocean initialization products to be performed in a 

dynamically active region. 

In this presentation, six different products are evaluated, including three HYCOM analyses 

(Navy 0.08° global, Navy 0.04° GoM, NOAA/NCEP Atlantic RTOFS) and three other model 

types (NRL IASNFC NCOM, NCSU SABGOM ROMS, and NOAA/NOS NGOM POM). 

Evaluation of these products through comparison to P-3 profiles and AOML cruise observations 

demonstrates that the Navy HYCOM products consistently display the smallest bias and RMS 

errors relative to observations. In contrast, the NOAA/EMC RTOFS HYCOM displayed the 

largest bias and RMS errors as a result of known code problems. This problem has negatively 

impacted development of the HYCOM-HWRF coupled forecast model that uses RTOFS to 

provide initial fields. Fortunately, this problem should be cured when the planned transition of 

RTOFS HYCOM to the Navy global HYCOM system at EMC occurs during 2011. As of this 

writing, the Navy global HYCOM system produces the smallest bias and RMS errors compared 

to observations in the eastern Gulf of Mexico. 


Validation of Coupled Hurricane Atmosphere – Ocean Model (HyHWRF) 

Hyun-Sook Kim, D. Iredell, Y. Kwon, L. Liu, Q. Liu, C. Lozano, J. O’Connor, J. Sims, V. 

Tallapragada, B. Tuleya, Z. Zhan 

(hyun.sook.kim@noaa.gov) 

NOAA/NCEP/EMC 

Under a goal toward the next generation of operational HWRF (Hurricane Weather 

Research Forecasting) Model, a collaboration effort has been made for the past years between 

the Marine Modeling and Analysis Branch and HWRF teams to build a framework of state-ofthe-art 

hurricane prediction model. HyHWRF includes air-sea interactive processes explicitly by 

coupling the atmospheric hurricane model HWRF to the ocean model HYCOM. In addition to 

the necessity of adopting physics-driven ocean model to provide a better realization of mesoscale 

sea surface temperature, for example, a motivation of the effort is to utilize unique leverage 

that is offered by our organization NCEP (National Centers for Environmental Prediction). The 

hurricane HYCOM is nested to eddy-resolving, Atlantic basin model, RTOFS (Real-Time Ocean 

Forecast System). NCEP runs RTOFS daily in real-time, using data assimilation including 

remote-sensing, in-situ and moored measurements, and generates ocean products such as sea 

surface temperature and sub-ocean properties. This infrastructure provides tremendous efficiency 

to coupled system in running in real-time, owing to streamline supply of initial and boundary 

conditions. 

Since the HyHWRF system has reached to a maturity in 2008, hundreds of the Atlantic 

tropical cyclone (TC) predictions have been performed. Also have been conducted in parallel to 

operational HWRF real-time forecast and operational implementation test each year. The results 

exhibit a comparable or better forecast skill to operational HWRF. This poster documents 

validation of ocean simulations. Sea surface temperature, upper ocean structure as well as ocean 

cooling are evaluated against available data including AXBT (Airborne eXpendable Bathy 

Thermograph), AVHRR and AMSR-E remote-sensing data. 


HWRF Model Diagnostic Improvements 

Janna O’Connor and Vijay Tallapragada 

(janna.oconnor@noaa.gov) 

NOAA/NCEP/EMC 

The hurricane team at EMC works to continually improve the HWRF model for each 

hurricane season. A crucial way of determining model behavior and potential areas of 

improvement is through the HWRF diagnostics suite. The evolution of the HWRF model 

diagnostics will be detailed, specifically the previous season’s inclusion of model-simulated 

GOES infrared and water vapor images. Potential upgrades for the 2011 hurricane season are 

described and involve a diagnostic module comparing three models side by side through vertical 

cross sections of relative humidity and wind speed, streamlines, and surface winds. The use of a 

new module that retrieves relevant pressure level data from model grib files and inserts them into 

an easy-to-read text file will also be explained. These upgrades coupled with the HWRF realtime 

statistics website will provide a new basis to assess model behavior and pinpoint areas of 

improvement with the goal of making HWRF updates more efficient and effective. 


Evaluating Experimental Models for Tropical Cyclone Forecasting in Support of the 

Hurricane Forecast Improvement Project (HFIP) 

Paul A. Kucera, Barb G. Brown, Louisa Nance, Christopher L. Williams, Kathryn Crosby, and 

Michelle Harrold 

(pkucera@ucar.edu) 

National Center for Atmospheric Research/ Research Applications Laboratory 

In 2009, the National Center for Atmospheric Science (NCAR)/Research Applications 

Laboratory’s (RALs) Joint Numerical Testbed (JNT) Program formed a new entity called the 

Tropical Cyclone Modeling Team (TCMT). The focus of this team is testing and evaluation of 

experimental models for tropical cyclone forecasting. TCMT evaluations may include models 

that are either in earlier stages of development or may not be intended for future operational 

application in the U.S. Much of this effort is sponsored by NOAA's Hurricane Forecast 

Improvement Project (HFIP). For the HFIP, the TCMT designs model evaluation experiments 

and provides general testing and evaluation of the various forecast models included in the HFIP 

annual forecasting demonstrations and retrospective experiments. Utilizing staff expertise in 

forecast verification, statistics, and atmospheric sciences, the TCMT is developing statistical 

approaches that are appropriate for evaluating a variety of tropical cyclone forecast attributes. 

These methods include new diagnostic tools to aid, for example, in the evaluation of track and 

intensity errors, precipitation and tropical cyclone structure forecasts. The TCMT also supports 

HFIP through other activities such as communicating results and providing a repository of model 

output and diagnostic information through a web-based data service site. The data service site 

will include model forecasts and some observational datasets as well as links and pointers to 

additional observational datasets. During 2010, the TCMT conducted an evaluation of a suite of 

experimental models that were candidates for future inclusion into the operational forecasting 

system at the National Hurricane Center (NHC). This retrospective analysis was conducted 

using a subset storms selected by NHC from the 2008 and 2009 tropical storms and hurricanes 

observed in the Atlantic and Eastern Pacific basins. In summary, the TCMT focuses on 

developing new methods for the evaluation of hurricanes, on the evaluation of experimental 

model forecasts for the annual HFIP retrospective and demonstration experiments, and on 

developing a hurricane database from these studies. An overview of TCMT activities along 

with a summary of results from the 2010 retrospective analysis will be given in the presentation. 


A highly configurable vortex initialization method for tropical cyclones 

Eric D. Rappin, David S. Nolan and Sharanya J. Majumdar 

(erappin@rsmas.miami.edu) 

University of Miami, RSMAS 

In order to provide realistic numerical predictions of tropical cyclone (TC) structure and intensity 

change, an accurate specification of the initial TC structure in a high-resolution model is 

necessary. The current capabilities of observational data (particularly when aircraft are not 

present) and data assimilation schemes preclude this from being achievable without considerable 

theoretical effort and computational expense. For many research and forecasting applications, a 

convenient but imperfect solution is the initialization of the model with a synthetic vortex. 

In this study, a customizable approach towards vortex initialization is employed, beginning with 

a user-specified, relocatable vortex in gradient wind balance that is constructed to be consistent 

with operationally estimated parameters. The tangential circulation can be extended upwards 

through a variety of idealized configurations of vertical structure. Next, a three-dimensional 

wind structure in the hurricane boundary layer is derived using Monin-Obukhov similarity 

theory, based on the gradient wind profile, variations in boundary layer depth, surface 

momentum flux and eddy viscosity. Finally, the relative humidity in the tropical cyclone can be 

configured. In the future, the mid- and upper-tropospheric secondary circulation will be derived 

from analyses based on satellite-derived atmospheric motion vectors. 

Simulations using the Weather Research and Forecasting (WRF) model will be presented. It is 

proposed that a well-constructed initial vortex will serve as a convenient benchmark against 

which new, sophisticated data assimilation schemes can be evaluated. 


Diagnosis of Operational Model Track Forecast Error for Hurricane Ike (2008) 

Michael J. Brennan 1 and Sharanya J. Majumdar 2 

(Michael.brennan@noaa.gov) 

1 NOAA/NWS/NCEP/NHC; 2 RSMAS Division of Meteorology and Physical Oceanography, 

University of Miami 

The National Hurricane Center (NHC) issues track forecasts every six hours for all active 

tropical cyclones in its area of responsibility. These forecasts are made at projection times of 12, 

24, 36, 48, 72, 96, and 120 hours. On 9 September 2008 track forecast errors from numerical 

model track guidance and the NHC’s official forecast for Hurricane Ike increased substantially 

compared to errors from forecasts during the previous couple of days. This period of elevated 

track error occurred three to four days prior to Ike’s Texas landfall early on 13 September. 

During this time, much of the track model guidance and the official NHC forecasts demonstrated 

a southward bias, taking the center of Ike to a landfall location along the central or southern 

Texas coast, instead of the upper Texas coast near Houston/Galveston where landfall ultimately 

occurred. The average error of the NHC 72-h track forecasts issued on 9 September was 92.8 

nm, a 38% increase in the average error compared to the NHC 96-h track forecasts issued on the 

previous day (66.8 nm). Errors from many of the track models were even larger; the average 

72-h forecast error for the interpolated GFS (GFSI) model on 9 September was 131.5 nm. This 

increase in track forecast error occurred during a critical time when federal, state, and local 

government agencies were making mitigation and disaster response decisions. 

Examination of the 500-hPa height analyses from the members of the NCEP Global 

Ensemble Forecast System (GEFS) at 0000 UTC 9 September 2008 show significant spread in 

the strength of the mid-level subtropical ridge over the southern United States north of Ike. 

Ensemble members that showed a stronger (weaker) ridge north of Ike during the model 

integration moved Ike on a track farther to the left (right) of the track of the GEFS ensemble 

mean, which was close to the actual track of Ike. Given these observations, an experiment was 

performed where the initial conditions in the GFS run from 0000 UTC 9 September were altered 

to slightly weaken the ridge north of Ike. Results from this experiment showed Ike moving 

significantly to the right of the operational GFS forecast from that time and closer to the 

observed track of the hurricane. Additional experiments perturbing other synoptic scale features 

possibly impacting the track of Ike had limited impact on the hurricane’s track. These results 

suggest that the evolution of the subtropical ridge was critical to determining Ike’s ultimate 

track. This case also represents an instance where a single-model ensemble system provided 

value over the typically superior multi-model consensus aids for TC track forecasting. 


An Update on the Status of FNMOC Projects to Improve Tropical Cyclone Forecasting 

Carey Dickerman 1 ; Paul Wittmann 1 ; Buck Sampson 2 ; Ben Ruston 2 

1 Fleet Numerical Meteorology and Oceanography Center; 2 Naval Research Laboratory, Marine 

Meteorology Division 

This poster will describe the progress of four projects at Fleet Numerical Meteorology and 

Oceanography Center (FNMOC) aimed at improving tropical cyclone forecasting. Two of the 

studies relate to the Geophysical Fluid Dynamics Laboratory (GFDL) hurricane model (GFDN) 

that has provided operational guidance since 1996 for storms in all basins, including the Indian 

Ocean and Southern Hemisphere (Rennick, 1999). This makes GFDN the only moveable 

tropical cyclone model running in all tropical oceanic basins worldwide. 

The first study investigates the relationship between forecast track error in nautical miles and 

intensity error in knots. Specifically, the study attempts to identify whether or not there is a 

relationship between track error and intensity error. The second study, specific to GFDN, 

analyzes the sensitivity of wind radii on track and intensity error. Particularly poor “outlier” 

forecasts during the 2010 season have been identified for analysis. The goal of the study is to 

isolate if the size of the 34-knot wind radii used to initialize GFDN have an important effect on 

the track and intensity forecasts. 

The third component of this poster is an overview of the status of tropical cyclone (TC) wave 

modeling at FNMOC. The prediction of TC wind-generated waves have long been a major 

concern for US Navy vessels and installations. Currently, wave models such as the Wave 

Prediction Model (WAM) and Wave Watch III (WW3) models (Tolman, et al., 2007) are driven 

by individual Numerical Weather Prediction models such as the Navy Operational Global 

Atmospheric Prediction System (NOGAPS) model (Rosmond, et al., 2002) or the Coupled 

Ocean/Atmosphere Mesoscale Prediction System (COAMPS) model (Naval Research Lab, 

2003). The TC track and intensity forecasts by these models may differ significantly from the 

official track issued by JTWC and NHC. Hence, the waves forecast will be inconsistent with the 

official track. The goal of this project is to create a wave forecast consistent with the official 

track. The method used to do this is as follows. 1) Interpolate the wind radii from the official 

track to a high resolution grid. 2) Remove the TC vortex from the global NWP model (NOGAPS 

or GFS). 3) Blend the high resolution interpolated winds into the background wind field. 4) 

Force the WW3 wave model, on a regional grid, using the blended wind grids. Results will be 

detailed in the poster. 

The fourth project that is described in this poster details the method of data assimilation and its 

potential effect on improving TC forecasting. The assimilation of Global Positioning System 

(GPS) bending angle has been a positive constraint on the moisture and temperature fields 

between 8 and 30 km (Healy, et al., 2007). After the GPS bending angle assimilation was added 

to the NAVDAS-AR (Xu, Rosmond, Daley et al., 2005) system it was possible to increase the 

spectral coverage from radiance data from all microwave and infrared sounders. The process is 

detailed in the poster. 


Improving the Assimilation of High-Resolution Satellite Wind Data into Mesoscale 

Prediction Models 

Ting-Chi Wu 1 , Hui Liu 2 , Christopher S. Velden 3 , 

Sharanya J. Majumdar 1 and Jeffrey Anderson 2 

(twu@rsmas.miami.edu) 

1 University of Miami, RSMAS; 2 National Center for Atmospheric Research; 

3 University of Wisconsin, CIMSS 

Given that tropical cyclones (TC) spend most of their lifetimes over the ocean, the assimilation 

of high-resolution satellite data is necessary to provide accurate model analyses of the TC 

structure and its environment. An example is cloud-derived Atmospheric Motion Vectors 

(AMVs) prepared hourly by CIMSS, with additional AMVs from rapid-scan mode included 

when available. The Ensemble Kalman Filter (EnKF) in the Weather Research and Forecasting 

(WRF) model is used to assimilate these high-frequency and high-resolution satellite data. 

The case chosen for this study is Typhoon Sinlaku (2008) during its period of intensification. In 

order to evaluate the influence of assimilating the experimental AMV data, a ‘control’ EnKF 

cycle is first produced with the assimilation of conventional observations (radiosonde, aircraft 

data, JTWC advisory TC position and operational JMA cloud winds). Next, a parallel EnKF 

cycle that also includes the experimental CIMSS AMVs is computed over the life cycle of 

Sinlaku. In order to offer a benchmark for the EnKF, a deterministic WRF run initialized from 

ECMWF is also produced. 

Both the ‘Control’ and ‘experimantal CIMSS-AMV’ ensemble forecasts generally produce lower 

track errors than the deterministic run. Additionally, the ensemble forecasts exhibit a shorter 

spin-up time than the deterministic run in terms of intensity, with stronger wind structures. A 

comparison between the structures of Sinlaku in the respective EnKF analyses will be presented, 

and analyzed with respect to dropwindsonde observations during the TCS-08/T-PARC field 

campaign. The influence of assimilating the experimental CIMSS-AMV datasets on the 

ensemble forecasts of Sinlaku will also be presented. 


Diagnosing initial condition sensitivity of Typhoon Sinlaku (2008) and Hurricane Ike 

(2008) 

William A. Komaromi, Sharanya J. Majumdar and Eric D. Rappin 

(wkomaromi@rsmas.miami.edu) 

Rosenstiel School of Marine and Atmospheric Science, University of Miami 

An examination of the sensitivity of numerical simulations of tropical cyclone (TC) track 

to perturbations in the initial conditions has been conducted for Typhoon Sinlaku (2008) and 

Hurricane Ike (2008). Balanced perturbations of different amplitude, spatial scale and location 

were created via a modification of local relative vorticity at a chosen location and depth. For 

each TC, 5-day Weather Research and Forecasting (WRF) model track predictions are compared 

to an unperturbed (“control”) simulation. The control simulations replicate forecast errors 

evident in the operational models specific to the chosen TCs, including a premature recurvature 

in the forecast for Sinlaku and a landfall too far south along the Texas coast for Ike. 

In the case of Typhoon Sinlaku (2008), the premature recurvature in the control 

simulation is found to be corrected by a variety of initial perturbations, including the weakening 

of an upper-level low directly to its north and the weakening of a remote shortwave trough in the 

mid-latitude storm track. It is suggested that one or both of the shortwaves may have been 

initialized too strongly. In the second case, Hurricane Ike (2008) initialized four days prior to its 

landfall in Texas, the forecasts were not sensitive to most remote perturbations. The primary 

corrections to the track of Ike arose from a weakening of a mid-level ridge directly to its north, 

and the strengthening of a shortwave trough in the mid-latitudes. For both Sinlaku and Ike, 

targets selected objectively by the Ensemble Transform Kalman Filter (ETKF) were often but 

not always consistent with the most sensitive regions found in this study. 

The methodology employed by this study may be used retrospectively by the research 

and operational communities to offer suggestions on the weather features in which the initial 

analysis required improvement, via a combination of improved modelling, observational 

coverage or data assimilation. The diagnostic technique may also be used to improve 

understanding of objective sensitivity methods, such as Singular Vectors and the ETKF, and 

their limitations. 


Testing of a New Parametric Tropical Cyclone Wind Model for Implementation 

in the Gradient Wind Asymmetric Vortex Algorithm (GWAVA) 

to Drive Storm Surge Prediction Models 

Craig A. Mattocks 1 , Vincent T. Wood 2 

(cmattock@rsmas.miami.edu 

1 University of Miami/Rosenstiel School of Marine and Atmospheric Science; 

2 NOAA/OAR/National Severe Storms Laboratory 

A new tropical cyclone wind model, 

developed at the National Severe Storms 

Laboratory (NSSL), is presented that is 

primarily designed to depict realisticlooking 

tangential wind profiles that can 

better fit the wind structure around a tropical 

cyclone. The parametric wind profile 

employs five key parameters: maximum 

tangential wind, radius of maximum 

tangential wind (RMW), and three powerlaw 

exponents that shape different portions 

of the velocity profile. One of the exponents 

explicitly controls the broadness and 

sharpness of the peak locally in the annular 

zone that encompasses the tangential wind 

maximum. 

To assess the performance of the new 

parametric wind model, gridded H*Wind 

horizontal wind analyses for Tropical Storm 

Dolly (2008), Hurricanes Katrina (2005), 

Ike (2008), Danielle (2010), Earl (2010), 

and Igor (2010) were used as input. These 

tropical cyclones were chosen because the 

wind fields are highly asymmetric. The 

gridded fields were interpolated using a 

bilinear interpolation technique to construct 

each radial profile of total wind speed from 

the storm center defined in a cylindrical 

coordinate system. At each of 360 radial 

profiles, optimization of the initial five 

model parameters was performed using the 

Levenberg-Marquardt method that solves 

the nonlinear least squares problem for 

Poster Session – Page 24 

curve-fitting applications. The calculated 

root-mean-square errors were computed to 

evaluate the accuracy of the fitted and 

analytical tangential wind profiles. Using the 

fitted model parameters, a two-dimensional 

wind field was reconstructed by 

interpolating the 360 radial profiles to the 

Cartesian coordinate system. The parametric 

wind model has shown considerable skill in 

accurately replicating tropical cyclone wind 

fields that compare favorably with those in 

the H*Wind analyses (Fig. 1). This versatile 

wind model will soon be implemented in 

GWAVA to improve the wind forcing that 

drives storm surge prediction models. 

Fig. 1. Fit of the NSSL tropical cyclone 

parametric wind model to a horizontal wind field 

(kt) from an H*Wind analysis for Hurricane Ike 

(2008). Blue circle indicates the limited region 

in which the winds are fitted. TC stands for 

tropical cyclone

Objective Diagnosis of the Eyewall Replacement Cycle in Mature Tropical Cyclones 

Elizabeth R. Sanabia and Nicholas P. Celone 

(sanabia@usna.edu) 

United States Naval Academy 

Typhoon Sinlaku underwent an eyewall replacement cycle shortly before making landfall 

over Taiwan in September 2008 during the Tropical Cyclone Structure – 2008 (TCS-08) field 

program. Eyewall replacement cycles in tropical cyclones are often associated with intensity 

fluctuations and increased predictability challenges (Willoughby et al. 1982). Currently, 

microwave satellite imagery is an accepted and often effective means by which to detect various 

stages in the eyewall replacement cycle; however, the near 12-h temporal resolution and hit-ormiss 

spatial sampling of microwave sensors are insufficient to capture the detailed evolution of 

the eyewall replacement cycle process, which frequently lasts less than 24 h (Kossin and 

Sitkowski 2009). 

Here, the eyewall replacement cycle during TY Sinlaku is examined using differences in 

water vapor and infrared satellite brightness temperatures from geostationary sensors to detect 

deep convection that penetrates the tropopause (Fritz and Laszlo 1993; Olander and Velden 

2009). The geostationary data are transformed into a cylindrical grid about the storm center, and 

the water vapor – infrared differences are examined over varying radial bands. A new diagnostic 

technique is then used to map this deep convection over time. In the case of Typhoon Sinlaku, 

the deep convection is mapped during a 72-h period that includes the eyewall replacement cycle 

and provides clear evidence of inner eyewall decay as well as outer eyewall development and 

subsequent contraction. These results are compared with other satellite data and TCS-08 aircraft 

observations, and links between the evolution of deep convection and changes in intensity are 

assessed. 

The eyewall mapping technique is then extended to other cases to examine the potential 

for improving intensity forecast accuracy during eyewall replacement cycles. While diagnostic 

in nature, this eyewall mapping technique may be applied on a real-time basis and provide the 

forecaster with unique, objective insight regarding the evolution of a tropical cyclone throughout 

its lifecycle and be of particular use in the diagnosis of eyewall replacement cycles. The 

technique may also provide new insights into the behavior of deep convection and possible 

correlation to periods of rapid intensification and rapid decay. 

_____________ 

Fritz, S., and I. Laszlo, 1993: Detection of water vapor in the stratosphere over very high 

clouds in the tropics. J. Geophys. Res., 98 (D12), 22,959-22,967. 

Kossin, J. P., and M. Sitkowski, 2009: An objective model for identifying secondary 

eyewall formation in hurricanes. Mon. Wea. Rev, 137, 876-892. 

Olander, T. L. and C. S. Velden, 2009: Tropical cyclone convection and intensity 

analysis using differenced infrared and water vapor imagery. Wea. Forecasting, 

24, 1558-1572. 

Willoughby, H. E., J. A. Clos, and M. G. Shoreibah, 1982: Concentric eye walls, secondary wind 

maxima, and the evolution of the hurricane vortex. J. Atmos. Sci., 39, 395–411. 


Climatology of Hot Towers in Tropical Cyclone's Inner Cores and Rainbands Based on 12- 

year TRMM Data 

Cheng Tao and Haiyan Jiang 

(ctao003@fiu.edu) 

Department of Earth & Environment, Florida International University 

Recent studies have shown that hot towers may be an indicator of tropical cyclone (TC) 

genesis and intensification. Using a 12-year (December 1997 - December 2009) Tropical 

Rainfall Measuring Mission (TRMM) tropical cyclone precipitation feature (TCPF) database, hot 

towers in TCs are identified by using the TRMM PR observed maximum 20 dBZ echo height 

reaching four different reference heights, i.e., 14 km, NCEP reanalysis derived tropopause 

height, Level of Neutral Buoyancy calculated using NCEP sounding and surface equivalent 

potential temperatureθ e , Level of Neutral Buoyancy calculated usingθ e at 925 and 1000 mb, 

whichever is greater. The common properties of these extreme convective systems are examined 

in terms of geographical locations, different TC intensities, and different TC regions, i.e., the 

inner core (IC) region, the inner rainband region (IB), and the outer rainband region (OB). It is 

found that 13.2% of TC precipitation features reach 14 km, and 2.6% of them may even 

penetrate 16 km. Hot towers in TCs are more frequent in the Western North Pacific basin than 

any other TC-prone basins. The percentage of precipitation features with one or more hot towers 

is greater in the IC region than in the IB and OB regions by a factor of 10-20, depending on 

which reference height is used. It is also found that hot towers in the IC region have a higher 

mean maximum height of 20 and 40 dBZ echo, stronger ice scattering signature than in 

rainbands regions, no matter which reference height is used. The percentage of features with hot 

towers increases as TC intensity increases. The mean maximum height of 40 dBZ echo is higher 

in hurricanes than in tropical storms and tropical depressions. 


Quantitative Comparison of Precipitation Algorithms in Tropical Cyclones 

Joseph P. Zagrodnik and Haiyan Jiang 

(jzagr001@fiu.edu) 

Department of Earth and Environment, Florida International University 

The Tropical Rainfall Measurement Mission (TRMM) has been collecting Tropical 

Cyclone (TC) rainfall measurements since 1997. The Tropical Cyclone related Precipitation 

Feature (TCPF) database has been developed to process raw pixel-level satellite measurements 

into specific events that can be quickly sorted and compared. In addition, a semi-manual method 

has been used to divide 12 years of TC rainfall data into inner core (IC), inner rainband (IB) and 

outer rainband (OB) regions. The database consists of over 13,000 TC overpasses from 

December 1997 through December 2009. Using TCPF data, two TRMM rainfall retrieval 

algorithms are compared: The Version 6 TRMM Precipitation Radar (PR) 2A25 algorithm and 

the Version 6 TRMM Microwave Imager (TMI) 2A12 algorithm. 

In this study, the differences in tropical cyclone (TC) rainfall algorithms are evaluated in 

terms of physical location, storm intensity, sub-regions inside the storm (eyewall or rain bands, 

stratiform or convective), and the diurnal cycle. Consistent with previous studies, considerable 

differences are found to exist between the algorithms. For all TCs over oceans, the TMI 2A12 

algorithm produces the most volumetric rainfall, as it contains the highest mean rain rates in all 

TC intensity categories. The PR 2A25 algorithm contains a higher percentage of light (< 5 mms - 

1 ) rain rates, but compensates with a greater total rain area. The difference in rainfall algorithms 

is most significant in TC inner cores. Total volumetric rain was found to be highest in the for the 

PR 2A25 algorithm in TC inner cores, while the TMI 2A12 algorithm produces the highest 

volumetric rain for TC inner bands and outer bands. 


Numerical Studies of Lower Boundary Forcing on Tropical Storm Fay (2008) over 

Southern Florida 

Travis L. Washington and Sen Chiao 

(Twashington2008@my.fit.edu) 

Department of Marine and Environmental Systems 

Florida Institute of Technology 

This study is aimed to investigate the track and intensity changes of Tropical Storm Fay as it 

moved across south Florida. The maximum wind speed was achieved around 1800 UTC 19 

August when the center was near the western side of Lake Okeechobee. The overages of 

precipitation in the days before landfall left the soil moisture saturated ahead of TS Fay. Yet, the 

warmer SST over the lake as well as the west coast of Florida may have played a role in 

maintaining the intensity of the storm. It is our working hypothesis that the storm moved near 

Lake Okeechobee, and intensified or closely held its intensity due to high soil moisture, and 

warmer SST over Lake Okeechobee and the west coast of Florida. 

The simulations are performed using the Weather Research and Forecasting (WRF-ARW) model 

with 30, 10 and 3.3 km nested domains to examine our hypothesis. The FNL and the twelfthdegree 

RTG_SST analysis are adopted as the initial and lateral boundary conditions. The 

preliminary results demonstrate that the high-resolution simulation is able to recapture the track 

and deepening rate of the storm while passing through south Florida. The sensitivity experiments 

of land surface characters and SST in this case illustrate their impacts on the intensity and track 

of TS Fay during and after landfall. To further investigate the intensity changes experiment using 

the TC bogus approach were performed. The simulated results demonstrate that using the TC 

bogus approach the storm can effectively reach the intensity (e.g., low pressure center) as the 

NHC recorded. Nevertheless, the simulated track may still need to be improved. 


Vertical Wind Shear Impacts on Hurricane Structure Deduced from Airborne-Doppler 

and HWRF Databases 

Paul Reasor 1 , Rob Rogers 1 , Sylvie Lorsolo 2 , Sundararaman Gopalakrishnan 1 , 

John Gamache 1 , Frank Marks 1 

(paul.reasor@noaa.gov) 

1 NOAA/AOML/HRD, 2 CIMAS/HRD 

We will present the application of a newly-constructed database of radar-derived winds in 

hurricanes to the examination of structural characteristics of vertically sheared systems. At 

present, the database consists of over 150 passes of NOAA aircraft through hurricanes of varying 

strength. Metrics are developed to quantify the structure, including local shear, vortex tilt, and 

low-azimuthal-wavenumber wind components. A shear-relative composite analysis is performed, 

stratified according to large-scale shear magnitude, vortex strength and vortex size. As expected, 

stronger shear and weaker vortex strength tend to yield greater vortex tilt and a more pronounced 

quasi-steady vertical velocity asymmetry. Stronger vortices in particular exhibit a preference for 

tilt to the left of the large-scale, deep-layer shear vector. 

A similar analysis has been applied to a database of over 100 HWRF ICs with 9 km 

horizontal grid spacing. The HWRF IC database reproduces many aspects of shear-induced 

structure revealed in the Doppler database. This analysis is being extended to forecast fields 

using HRD’s experimental HWRF model at 3-km resolution. These results will be presented at 

the conference with the aim of clarifying HWRF’s representation of the vortex-shear interaction 

relative to that depicted by the radar database. 


Is hurricane rapid intensification possible 

from the energy released inside of a convective burst? 

Owen A. Kelley 1 , Jeffrey B. Halverson, 2 and John Stout 1 

(Owen.Kelley@nasa.gov) 

1 NASA Goddard Space Flight; 2 University of Maryland Baltimore County 

When a hurricane intensifies, the NHC forecast discussion sometimes mentions particularly 

vigorous convection being observed in the eyewall. When Hurricane Earl (2010) was 

intensifying to category 4 on its approach toward the U.S., the NHC discussion stated: "THE 

EYE HAS CONTINUED TO CLEAR AND IS SURROUNDED BY CLOUD TOPS TO -70 

DEGREES CENSIUS OR COLDER" [5 PM AST 30 Aug 2010]. Forecasters may mention such 

bursts of eyewall convection because they are common in infrared satellite animations of 

intensifying hurricanes. Or perhaps forecasters mention convective bursts because some of the 

intensity forecast schemes that forecasters rely on take into account the vigor of eyewall 

convection through various empirical parameterizations. It is still a subject of debate, however, 

what physical mechanisms connect convective bursts with energy flowing into the hurricane's 

tangential wind field. 

Even before there is scientific consensus on these physical mechanisms, it would be helpful to 

estimate what energy conservation and other thermodynamic considerations permit in terms of a 

convective burst's effect on hurricane intensity. This study provides such a thermodynamic 

estimate, incorporating recently collected satellite datasets, modeling studies, and analyses of 

multi-instrument wind observations. 

First, satellite observations provide estimates of the net amount of condensation occurring inside 

of a vigorous eyewall cell. Net condensation is proportional to net latent heat release. Making 

reasonable assumptions, a convective burst (a series of vigorous cells) could release 6e17 J of 

latent heat into the eyewall every 12 hours, in excess of the amount of latent heat that would 

have been released in the eyewall in the absence of a convective burst. Convective bursts have 

been observed to persist for 9 to 48 hours. Second, modeling studies provide estimates of the 

efficiency with which latent heat released in the eyewall may be transformed into increased 

kinetic energy of the hurricane's tangential wind. A 5% to 7% efficiency is consistent with 

recent modeling studies. Third, an examination of wind analyses provides a mapping between 

changes in kinetic energy and changes in surface wind intensity. An experimental extension of 

the H*wind analysis to three dimensions suggests a power-law relation between initial and final 

kinetic energy (KE) and initial and final surface wind intensity (I): KE f / KE i = ( I f / I i ) 1.34 . 

Putting these three pieces together, this study estimates that intensification at the rate of 11−19 m 

s -1 (21−37 kt) in 12 hours could result from the extra amount of latent heat that the convective 

burst releases inside of the eyewall. As a point of reference, rapid intensification is often 

considered ≥15 m s -1 (30 kt) in 24 hours, and some convective bursts persist for several days. 


Hurricanes: Science and Society – an online resource collaboratively developed by 

scientists, education and outreach professionals, and educators 

Isaac Ginis, G. Scowcroft, R. M. Yablonsky, C. W. Knowlton, H. Morin, 

(iginis@gso.uri.edu) 

Graduate School of Oceanography, University of Rhode Island 

There are many models for engaging scientists in education and outreach activities that can assist 

them in achieving broader impacts of their research. Successful models provide the participating 

scientists with an opportunity to contribute their expertise in such a way that there are long 

lasting effects and/or useful products from their engagement. These kinds of experiences 

encourage the scientific community to continue participating in education and outreach activities. 

Hurricanes: Science and Society is an education and outreach program funded by the National 

Science Foundation that has successfully assisted scientists in broadening the impacts of their 

work. It has produced a new online educational resource (Hurricanes: Science and Society 

website) that was launched in October 2010. This multi-disciplinary tool has been developed 

with the guidance and input from a panel of leading U.S. hurricane researchers and the 

participation of U.S. formal and informal science educators. 

This educational resource is expected to become a classroom tool for those both teaching and 

learning hurricane science. It contains information tailored for specific audiences including 

middle school through undergraduate educators and students, the general public, and the media. 

In addition to the website, a 12-page publication for policymakers and other stakeholders has 

been produced along with an accompanying CD-ROM/DVD to assist formal and informal 

science educators in maximizing the use of this new resource. Hurricanes: Science and Society 

can play a substantial role in the effort to educate both students and adults about the science and 

impacts of hurricanes and the importance of pre-hurricane planning and mitigation. 

http://www.hurricanescience.org 


The influence of cyclones on the BP oil spill 

Pat Fitzpatrick, Yee Lau, Chris Hill, and Haldun Karan 

(fitz@gri.msstate.edu) 

Geosystems Research Institute, Mississippi State University 

The Deepwater Horizon oil spill impacted the Mississippi River Delta, Barataria Bay, the barrier 

islands east of Louisiana, and the Alabama and Florida coast for an extended period of time from 

May through July. However, the Rigolets and western Mississippi coast were impacted for a 

briefer period from late June to early July. An important component to understanding the oil 

transport is to distinguish the influences behind this apex moment. A simulation was conducted 

for the period 20 June to 10 July 2010 to understand this inland transport. 

The simulation was based on a Lagrangian particle tracker with random walk diffusion. Input 

consisted of latitude and longitude positions of oil-contaminated parcels, wind, current, and a 

large array of random numbers. In addition, new parcels were released at the damaged Macondo 

rig location at each time step. Twenty-five parcels are released at each position, and when 

combined with the diffusion coefficient (set to 10m 2 s -1 ), resulted in a realistic spread of the 

parcels with time. The initial parcel locations were subjectively determined based on a 

combination of NASA MODIS satellite imagery, SAR imagery, NOAA oil trajectory maps, and 

the NOAA/NESDIS Satellite Analysis Branch (SAB) experimental surface oil analysis. The 

parcels were advected at 80% of the ocean current speed and at 3% of the wind speed. Bilinear 

interpolation was applied every timestep to determine the currents and winds at each parcel. The 

pseudo-random numbers were uniformly distributed between 0 and 1 and generated by the 

Mersenne Twister algorithm. The initial seed was randomly obtained from machine noise. 

The 10-m wind and near-surface ocean currents were provided from NAVOCEANO’s 3-km 

Navy Coastal Ocean Model (NCOM) in the Intra-Americas Sea (AMSEAS) domain, with 

atmospheric forcing from COAMPS. The wind forcing was validated against buoys using 

statistical and vector correlation techniques, concluding that the winds were reasonably accurate. 

An examination of NCOM data, the oil spill simulation, buoy data, weather reanalysis maps, tide 

gauge data, scatterometer data, and HF radar currents show that two weather systems altered the 

currents and water levels such that oil was pushed into the western Mississippi Sound and the 

Rigolets. An easterly wind fetch from intensifying Hurricane Alex provided the first inland push, 

followed by a westward-drifting non-tropical low which had formed off the western edge of a 

Gulf cold front. In both cases, a weak pressure gradient was replaced by strong easterly winds 

which not only switched alongshore westerly coastal currents to an easterly direction, but also 

increased inland water levels by 0.6-0.8 m as mini-surge events. These results showed that 

cyclones can dramatically alter oil transport, even by fringe effects. The study also showed that 

this modeling formulation was capable of reproducing the oil spill transport and is being used in 

follow-up BP research. 


SATellite Intensity CONsensus (SATCON) Evaluation and Recent Changes 

Derrick Herndon 1 , Chris Velden 1 , Jeffrey Hawkins 2 

1 Univ. Wisconsin Cooperative Institute for Meteorological Satellite Studies (CIMSS); 

2 Naval Research Laboratory - Monterey 

The SATellite CONsensus (SATCON) algorithm developed at CIMSS objectively combines 

Tropical Cyclone (TC) intensity estimates analyzed from satellite infrared and microwave-based 

methods to produce a weighted consensus estimate which is more skillful than the individual 

members. SATCON provides the TC forecaster with the ability to quickly reconcile differences 

in objective intensity methods, and as a comparative guidance tool for evaluating subjective 

Dvorak estimates. Real-time SATCON estimates have been provided to NHC, BOM and JTWC 

along with other TC forecast agencies as part of a demonstration phase since the 2008 TC 

season. 

Current members of SATCON include the CIMSS ADT along with the CIMSS and CIRA 

AMSU algorithms. Each member of SATCON is weighted based on that member’s performance 

in a given situation (eye size, intensity, infrared scene type, etc.). Separate weights are used for 

minimum pressure and maximum wind estimates. The SATCON algorithm logic and weighting 

structures were developed using coincident reconnaissance aircraft data from storms in the 

Atlantic, Eastern Pacific and Western Pacific. To date, we have accrued 562 cases when all three 

SATCON members were available and matched up with recon data. This dataset is divided into a 

dependent development sample, and an independent validation sample using a “leave every other 

case out” approach. 

In addition to updating the consensus weight structure as new cases become available, a number 

of recent changes have been made to further improve the MSW estimates. These upgrades, as 

well as the resultant performance statistics, will be summarized in the poster. Further information 

on SATCON can be found at: 

http://cimss.ssec.wisc.edu/tropic2/real-time/satcon/ 


A Methodology for Incorporating Hurricane Forecast Errors into Decision-Support 

Systems for Energy and Utility Companies 

A. B. Schumacher 1 , S. M. Quiring 2 

(schumacher@cira.colostate.edu) 

1 Cooperative Institute for Research in the Atmosphere; 

2 Department of Geography, Texas A&M University 

A variety of decision-support systems, such as those employed by energy and utility 

companies, utilize the National Hurricane Center (NHC) forecasts of track and intensity to 

inform operational decision-making as a hurricane approaches. Changes in hurricane intensity 

and track, especially just prior to landfall, can negatively impact the accuracy of these decisionsupport 

systems. This study demonstrates how the Monte Carlo wind speed probability 

(MCWSP) can be applied to develop probabilistic estimates of the impact of the approaching 

storm. Our methodology utilizes the 1000 individual forecast realizations generated by the 

MCWSP algorithm, instead of the wind speed probabilities, coupled with a power outage model 

to generate a distribution of power outage predictions for three past storms. Based on power 

outage data from a Gulf Coast utility company we found that the ensemble average was a better 

predictor of damage to the power system than predictions made using the official National 

Hurricane Center forecast. We believe that this methodology can be used to incorporate 

information about tropical cyclone forecast errors into decision support systems that utilize NHC 

track and intensity data. 


What might a global TC reanalysis project look like? 

Paula Ann Hennon 1 , Ken Knapp 2 

(paula.hennon@noaa.gov) 

1 STG, Inc.; 2 NOAA/NCDC/RSAD 

Tropical cyclone intensity, distribution and frequency significantly impact life and property. 

Understanding these aspects of cyclones, however, requires a uniformly constructed dataset. The 

International Best Track Archive for Climate Stewardship project has provided a centralized 

collection of TC best track data. Despite efforts to minimize discontinuities in IBTrACS, 

inhomogeneities remain caused by changes in instrumentation, personnel, forecast agencies and 

operational procedures, which has led to a catalog of storms that is incongruous. To ameliorate 

this issue, efforts are underway in the North Atlantic to perform a reanalysis of storm intensity, 

however no global effort is currently in progress. 

We plan to build upon work already in progress by NHC and HRD in conjunction with the 

National Climatic Data Center to facilitate the development of and to archive a record of reanalyzed 

global TC intensity. NCDC is uniquely positioned to facilitate this project given the 

datasets and expertise on hand. IBTrACS is a global inventory of known tropical cyclones, while 

the HURSAT dataset is a collection of all satellite brightness temperatures from polar and 

geostationary satellites for the storms in IBTrACS. Using these NCDC resources, the Dvorak 

technique can be applied to estimate TC intensity during the satellite era. 

NCDC’s extensive archive of in-situ data already in the process of being modernized by the 

Climate Data Modernization Program as well as data in the paper archives at yet to be discovered 

can be made available to the global tropical cyclone research community, but necessitates a 

coordinated multi-agency effort. 

What should we DO 

with this data? 


Getting the Surge Message Across 

Betty Hearn Morrow 1 , Jeff Lazo 2 , Jamie Rhome 3 

(betty@bmorrow.com) 

1 SocResearch Miami; 2 NCAR; 3 NOAA/NHC 

Major initiatives are underway to improve storm surge forecasting – and to find better ways to 

communicate surge risk to vulnerable coastal residents. Evidence continues to reveal that the 

public under-recognizes the dangers of storm surge. The most recent example is that 15,000 

people did not evacuate from Galveston Island for Hurricane Ike in spite of a forecast of up to 20 

feet of storm surge. The message regarding the 200+ deaths on the Mississippi coast from 

Hurricane Katrina’s surge was somehow lost. 

Acknowledgement of the need to better understand how people view forecasts and warnings has 

resulted in several on-going initiatives within the climate and weather enterprise including the 

social sciences portion of NOAA’s Storm Surge Roadmap project and several projects on 

Communicating Hurricane Information funded by the National Science Foundation. Research 

with coastal citizens, local emergency managers and others provides evidence that a major 

portion of the population does not understand the surge hazard adequately to take appropriate 

action. If improvements are not made in the public’s understanding of storm surge threat, 

extensive loss of life is likely to occur. Considerable research within numerous fields and 

disciplines from the social sciences has contributed to a better understanding of how people 

perceive and react to risk. This presentation will provide an overview of the research followed by 

a discussion of several initiatives underway within NOAA to improve the public’s understanding 

of the storm surge threat.

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