HRD Monthly Science Meeting of July 2014

July’s Science meeting had 4 presentations:

  1. Kelly M. Núñez Ocasio:  An Extreme Event in the Eyewall of Hurricane Felix
  2. Robert Nystrom:   Storm-Relative Correlation Structures
  3. Joseph Patton:  Extratropical Transition of Hurricane Sandy
  4. Robert Rogers:  Deep convection and its role in RI

The presentations are available on the anonymous ftp site at:

HRD Debrief for missions into Tropical Storm/Hurricane Arthur – 11 July 2014

HRD researchers discussed the results from the 5 P-3 and 4 G-IV missions into Tropical Storm/Hurricane Arthur. The agenda for the discussion was:

  • Missions Overview (Reasor)
  • Science Discussions
    • N42: TDR (Rogers/Bucci)
    • N43: TDR (Aberson/Zhang)
    • G-IV: TDR/ET (Gamache/Aberson)
  • Field Program Issues

HRD welcomes summer students



Left to right: Robert Nystrom, Joseph Patton, Kelly Nuñez Ocasio, and Michael Maier-Gerber.

HRD is hosting four students this summer as part of various NOAA programs and collaborations with research partners.

Robert Nystrom is a NOAA Hollings Scholar from the University of Illinois at Urbana-Champaign.  He is working with Altug Aksoy to investigate storm-relative correlation structures in ensembles of idealized hurricane simulations.

Joseph Patton is also a NOAA Hollings Scholar, and hails from the University of Oklahoma.  He is working with Sim Aberson to study the extratropical transition of Hurricanes Sandy using HEDAS analyses.

Kelly Nuñez Ocasio is a NOAA Education Partnership Program Scholar from the University of Puerto Rico-Mayagüez.  She is working with Jun Zhang and Sim Aberson on data from the P-3 flight into Hurricane Felix that was aborted due to turbulence.

Michael Maier-Gerber is an undergraduate student at the Institute for Meteorology and Climate Research at the Karlsruhe Institute of Technology, Karlsruhe, Germany.  He is examining the structure and evolution of Hurricane Ingrid (2013) to elucidate how Ingrid was able to intensify under the influence of sustained shear.

We hope you all enjoy your time at HRD and learn a lot about hurricanes to take with you in your future careers.

HRD seminar – Jun Zhang, CIMAS and AOML/HRD – 29 May 2014

Jun presented a seminar on “A Developmental Framework for Improving Hurricane Model Physical Parameterizations using Aircraft Observations”


As part of NOAA’s Hurricane Forecast Improvement Program (HFIP), this paper addresses the important role of aircraft observations in hurricane model physics validation and improvement. A model developmental framework for improving the physical parameterizations using quality-controlled and post-processed aircraft observations is presented, with steps that include model diagnostics, physics development, physics implementation and further evaluation. Model deficiencies are first identified through model diagnostics by comparing the simulated axisymmetric multi-scale structures to observational composites. New physical parameterizations are developed in parallel based on in-situ observational data from specially designed hurricane field programs. The new physics package is then implemented in the model, which is followed by further evaluation. The developmental framework presented here is found to be successful in improving the surface layer and boundary layer parameterization schemes in the operational Hurricane Weather Research and Forecast (HWRF) model. Observations for improving physics packages other than boundary layer scheme are also discussed.

A video recording of the presentation is available on the anonymous ftp site:

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HRD seminar – Jun Zhang, CIMAS and AOML/HRD – 15 May 2014

Jun presented a seminar on “Asymmetric hurricane boundary layer structure relative to the  wind shear from dropsonde composites


This talk presents the asymmetric structure of the hurricane boundary layer in relation to the environmental vertical wind shear in the inner core region. GPS dropsonde data deployed by research aircraft in 19 hurricanes are analyzed in a composite framework. Kinematic structure analyses based on Doppler radar data from 96 eyewall penetration legs are compared with the dropsonde composites. Shear-relative quadrant-mean composite analyses indicate that both the kinematic and thermodynamic boundary layer height scales tend to decrease with decreasing radius, consistent with previous axisymmetric analyses. There is still a clear separation between the kinematic and thermodynamic boundary layer heights. Both the thermodynamic mixed layer and the height of maximum tangential wind speed are within the inflow layer. The inflow layer depth is found to be deeper in quadrants down shear, with the downshear right (DR) quadrant being the deepest. The mixed layer depth and height of maximum tangential wind speed are alike at the eyewall, but are deeper outside in quadrants left of the shear. The results suggest also that air parcels acquire equivalent potential temperature (θe) from surface fluxes as they rotate through the upshear right (UR) quadrant from the upshear left (UL) quadrant. Convection is triggered in the DR quadrant in the presence of asymmetric mesoscale lifting coincident with a maximum in θe. Energy is then released by latent heating in the downshear left (DL) quadrant. Convective downdrafts bring down cool and dry air to the surface and lower θe again in the DL and UL quadrants. This cycling process may be directly tied to shear-induced asymmetry of convection in hurricanes.

An audio recording of the presentation is available on the anonymous ftp site:

and a copy of the presentation is also available at:

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HRD seminar – Paul Reasor & Altug Aksoy, AOML/HRD – 15 May 2014

Paul and Altug each presented a seminar:

  • “Evaluation of shear-relative hurricane structure from the HWRF model” – Paul Reasor


This talk will present a composite-based analysis of shear-relative hurricane structure from the HWRF model. The model’s representation of shear-relative precipitation and kinematic structure are evaluated using a recently-published composite of such structure diagnosed from airborne Doppler radar. Results stratified by shear magnitude, motion direction and vortex intensity are examined in addition to the total-case composite. Differences between the model and observed shear-induced asymmetries, including the vortex tilt, are interpreted in the light of differences in the typical environmental and symmetric vortex properties of the respective databases. Given the availability of HWRF model output at regular intervals, the talk is concluded with a composite-based examination of the relationship between temporal changes in vortex tilt and changes in hurricane structure and intensity.

A video recording of Reasor’s presentation is available on the anonymous ftp site:

  • “Model Sensitivity in Idealized, Ocean-Coupled Hurricane Simulations: Perturbations of Environment, Structure, and Model Physics Parameters” – Altug Aksoy


Idealized simulations are important tools to investigate in detail the dynamical evolution of a tropical cyclone for various environmental and/or structural characteristics. We present here a systematic sensitivity analysis using an idealized version of the Hurricane Weather Research and Forecasting (HWRF) model. The tropical cyclone environment is initialized with the tropical moist sounding of Dunion (2011, J. Climate). The westerly 850-200-hPa vertical wind shear is thermally balanced in the meridional direction. The zonal wind field is adjusted to yield a vertically integrated westward mean flow typical of Tropical Atlantic hurricanes. Lateral boundaries are forced with the same initial environmental profiles as in the computational domain interior to minimize imbalances. Coupling with a one-dimensional column ocean model introduces ocean cooling due to surface wind stress and modifies surface fluxes. The ocean column is initialized with prescribed temperature and salinity profiles that exhibit hurricane-season Tropical Atlantic characteristics with a deep, well-mixed upper ocean. The initial vortex is a wavenumber-0 composite of thousands of hurricane reconnaissance (dropwindsonde and tail Doppler radar) observations and historical height-radius cross-sections of steady-state, category-one Tropical Atlantic hurricanes over water. An analysis of the 5-day control simulation obtained in this manner will be presented first.

Model sensitivity to perturbations in parameters that include magnitude of zonal shear, vertically integrated atmospheric mean flow (storm speed), initial SST, environmental low-level and mid-level moisture and temperature, initial intensity, initial radius of maximum wind (RMW), as well as model parameters that control horizontal diffusion, vertical eddy diffusivity, and exchange coefficients of surface momentum and heat flux is then investigated, especially focusing on the quasi-steady-state regime that is observed in the 48-96 hours of the control simulation. Detailed analyses of parameter-model correlations, simulation spread, and response function will be presented for a systematic evaluation of model sensitivity. Suggestions will be made for calibrating the range of parameter values to improve the signal-to-noise ratio for the possibility of multiple, simultaneously perturbed parameters. Implications for ensemble-based data assimilation will be discussed.

A video recording of Altug’s presentation is available on the anonymous ftp site:

A video recording of the Q&A of both presentations is available on the anonymous ftp site:

AOML and HRD researchers at 31st AMS Conference on Hurricanes and Tropical Meteorology, San Diego, CA – 31 March – 4 April 2014

Sixteen HRD scientists participated in the recent 31st AMS Conference on Hurricanes and Tropical Meteorology, being authors or co-authors on 34 presentations and 9 posters.  Roughly 750 presentations (442 oral presentations in 70 sessions and 308 posters in 2 session) were submitted to the conference.

Of the 496 TC-related presentations and posters at the conference, 130, or about 26%, used data sets developed at HRD. There were 4 dedicated sessions to HFIP with 36 presentations, plus another 25-30 presentations sprinkled through the rest of the program that reported on HFIP and IFEX related work. It was also clear that HFIP research influenced a number of other presentations through recognition of the importance of evaluating numerical model system developments.

Recordings of the 34 presentations and the abstracts for the 9 posters AOML and HRD researchers presented (or were co-authors) at the Conference are available online from the AMS website.  Links to some of the posters can also be found below:

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HEDAS Analyses of a Rapidly Evolving Eyewall of a Major Hurricane – Fabian (2003) - Sim Aberson, NOAA/AOML/HRD, Miami, FL; and S. D. DitchekA. Aksoy, and K. J. Sellwood

Model Sensitivity to Perturbations of Environment, Structure, and Model Parameters in Idealized, Ocean-Coupled Tropical Cyclone Simulations - Altug Aksoy, NOAA/AOML and Univ. of Miami/CIMAS, Miami, FL; and B. W. KlotzJ. ZhangE. Uhlhorn, and J. J. Cione

Observing System Simulation Experiments to evaluate the impact of remotely sensed data on hurricane prediction - Robert Atlas, NOAA/AOML, Miami, FL; and T. Vukicevic, L. Bucci, B. Annane, A. Aksoy, J. Delgado, X. Zhang, and S. Gopalakrishnan

Sensing Hazards with Operational Unmanned Technology: NOAA’s multi-year plan to deploy the NASA Global Hawk aircraft for high impact weather - Michael L. Black, NOAA/AOML, Miami, FL; and G. A. Wick and R. E. Hood

A Study on the Asymmetric Rapid intensification of Hurricane Earl (2010) Using the HWRF system - Hua Chen, NOAA/AOML, Key Biscayne, FL; and S. Gopalakrishnan

The truth about 26C and the relative roles of the ocean and atmosphere at the hurricane air–sea interface - Joseph J. Cione, NOAA/HRD, Miami, FL

Quadrant distribution of tropical cyclone inner-core kinematics in relation to environmental shear - Jennifer C. DeHart, University of Washington, Seattle, WA; and R. A. Houze Jr. and R. F. Rogers

The Tropical Cyclone Diurnal Cycle - Jason Dunion, University of Miami/CIMAS-NOAA/HRD, Miami, FL; and C. D. Thorncroft and C. S. Velden

Correlation Between Named Storm Genesis Locations and Seasonal Atlantic Tropical Cyclone Activity: A Possible Link to Seasonal SAL Frequency - Evan B. Forde, NOAA/AOML/CSND, Miami, FL; and M. L. Black and J. Dunion

The Research HWRF system: Looking beyond the 10-m Wind Speed for Improved Storm Predictions - Sundararaman Gopalakrishnan, NOAA/AOML/HRD, Miami, FL; and X. Zhang, T. Quirino, V. Tallapragada, F. Marks, and R. Atlas

A Robust Observation Operator and Associated Background Covariances to Assimilate Microwave Radiances into Cloud-permitting Models - Ziad S. Haddad, JPL, Pasadena, CA; and J. Steward, T. Vukicevic, and S. Hristova-Veleva

Analysis of Shear-Relative Asymmetries in Tropical Cyclone Eyewall Slope Using Airborne Doppler Radar Data - Andrew Todd Hazelton, Florida State Univ., Tallahassee, FL; and R. F. Rogers and R. E. Hart

Climatological depiction of hurricane structure from passive microwave and scatterometer observations: Using the 12-year JPL Tropical Cyclone Information System (TCIS) to create composites and establish reliable statistics - Svetla Hristova-Veleva, JPL, Pasadena, CA; and B. Stiles, T. P. Shen, F. J. Turk, Z. Haddad, S. Gopalakrishnan, T. Vukicevic, Z. Wang, P. P. Li, B. W. Knosp, Q. A. Vu, and B. H. Lambrigtsen

Interhemispheric teleconnections from Atlantic Warm Pool heat source in intermediate and simple models - Xuan Ji, University of California Los Angeles, Los Angeles, CA; and J. D. Neelin, S. K. Lee, and C. R. Mechoso

Assessing the relationship between the large-scale and inner-core estimates of vertical shear - John Kaplan, NOAA/AOML/HRD, Miami, FL; and P. Reasor and M. DeMaria

Further Improvement of SFMR Surface Wind Speeds in Heavy Precipitation - Bradley W. Klotz, NOAA/AOML – Univ. of Miami/CIMAS, Miami, FL; and E. W. Uhlhorn, R. A. Black, and S. Lorsolo

Analysis of hurricane morphology, internal waves and boundary layer rolls observed from satellite SAR images - Xiaofeng Li, Global Science and Technology, Inc., College Park, MD; and Z. Zhao, B. Liu, J. Zhang, X. yang, W. Pichel, and M. DeMaria

Understanding Hurricane Sandy’s Track and Intensity Changes - Frank Marks, NOAA/AOML/HRD, Miami, FL

Tropical Cyclone Predictions over Indian Seas: Super Storm Phailin and beyond - U. C. Mohanty, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha, India; and K. K. Osuri, S. Pattanayak, S. Gopalakrishnan, D. Niyogi, Y. V. Ramarao, V. Tallapragada, and F. D. Marks Jr.

Role of Land Surface Processes on land falling Tropical Cyclones and Monsoon Depressions over the Indian Region - Krishna K. Osuri, Indian Institute of Bhubaneswar, Orisha, India; and U. C. Mohanty, S. Pattanayak, S. Gopalakrishnan, and D. Niyogi

On the limits of measuring the maximum wind speeds in hurricanes - David S. Nolan, Univ. of Miami/RSMAS, Miami, FL; and J. A. Zhang and E. W. Uhlhorn

Dynamic storm surge prediction with one-way coupled mesoscale modeling system - Sujata Pattanayak, Indian Institute of Technology Bhubaneswar, Bhubaneswar, Odisha, India; and U. C. Mohanty, K. K. Osuri, S. Gopalakrishnan, and D. Niyogi

Hurricane measurements and modeling for offshore wind farm development - Mark Powell, NOAA/AOML/HRD, Tallahassee, FL; and S. Murillo and S. Cocke

Evaluation of shear-relative hurricane structure from the HWRF model - Paul Reasor, NOAA/AOML/HRD, Miami, FL; and X. Zhang and S. Gopalakrishnan

Multiscale Structure and Evolution of Earl (2010) during Rapid Intensification - Robert F. Rogers, NOAA/AOML/HRD, Miami, FL; and P. D. Reasor and J. Zhang

A Balanced Vortex approach to Improving the Initial Condition and Diagnosing Forecasts in the Hurricane Research Weather and Forecasting Model - Kathryn J. Sellwood, Univ. of Miami/CIMAS and NOAA/AOML/HRD, Miami, FL; and T. Vukicevic

Idealized Study of Land Surface Impacts on Tropical Cyclone Intensity Predictions Using the HWRF Modeling System Subashini Subramanian, Purdue University, West Lafayette, IN; and S. Gopalakrishnan, G. R. Halliwell Jr., and D. Niyogi

Evaluating Different Convective Indicators of Tropical Cyclone Rapid Intensification: The Case of Hurricane Earl (2010) - Gabriel Susca-Lopata, University of Utah, Salt Lake City, UT; and E. Zipser and R. F. Rogers

Significant Advances to the NCEP Operational HWRF Modeling System for Improved Hurricane Forecasts - Vijay Tallapragada, NOAA/NWS/NCEP/EMC, College Park, MD; and S. Trahan, Y. C. Kwon, Z. Zhang, C. Kieu, Q. Liu, W. Wang, M. Tong, D. Sheinin, E. Liu, B. Zhang, S. Gopalakrishnan, X. Zhang, L. R. Bernardet, R. M. Yablonsky, J. W. Bao, R. J. Pasch, J. L. Franklin, D. A. Zelinsky, B. Strahl, W. Lapenta, R. L. Gall, and F. Toepfer

Improved Telescopic Nesting and Accurate Storm Tracking in the NCEP Operational HWRF Model - Samuel Trahan, NCEP EMC (IMSG), College Park, MD; and Z. Zhang, Y. C. Kwon, H. Y. Chuang, V. Tallapragada, T. Marchok, X. Zhang, S. Gopalakrishnan, and G. Thompson

Use of Synthetic Profiles to Diagnose Simulated Tropical Cyclones in Regional Hurricane Models - Jonathan L. Vigh, NCAR, Boulder, CO; and C. KieuV. Tallapragada, L. R. Bernardet, and E. W. Uhlhorn

The Global Hawk Airborne Vertical Atmospheric Profiling System: Status and Initial Applications - Gary A. Wick, NOAA/ESRL/PSD, Boulder, CO; and T. Hock, M. L. Black, J. Wang, J. R. Spackman, and R. E. Hood

Dropsonde composites of asymmetric hurricane boundary layer structure in relation to environmental vertical wind shear - Jun Zhang, NOAA/AOML and Univ. of Miami/CIMAS, Miami, FL; and R. Rogers, P. Reasor, E. Uhlhorn, and F. Marks

Representing Multi-Scale Interactions in HWRF Modeling System - Xuejin Zhang, NOAA/AOML/HRD, Miami, FL; and T. Quirino, Q. Liu, R. St. Fleur, Z. Zhang, and S. Gopalakrishnan


HEDAS Vortex-Scale Data Assimilation with Aircraft and Satellite Retrieval Observations: Summary of the 2013 Atlantic Hurricane Season Results - Altug Aksoy, NOAA/AOML and Univ. of Miami/CIMAS, Miami, FL; and S. AbersonK. SellwoodB. W. KlotzT. Vukicevic, and C. S. Velden  [poster available here]

The Satellite Proving Ground at the National Hurricane Center - John L. Beven, NOAA/NWS, Miami, FL; and M. J. Brennan, H. D. Cobb III, M. DeMaria, J. Knaff, A. B. Schumacher, C. Velden, S. A. Monette, J. P. Dunion, G. J. Jedlovec, K. K. Fuell, and M. J. Folmer

Development of a Tropical Cyclone Genesis Index (TCGI) for the North Atlantic - Jason Dunion, University of Miami/CIMAS-NOAA/HRD, Miami, FL; and J. Kaplan, A. B. Schumacher, J. Cossuth, and M. DeMaria

Wave and Wind Direction Effects on SFMR Brightness Temperatures - Heather M. Holbach, Florida State University, Tallahassee, FL; and E. Uhlhorn and M. A. Bourassa

Enhancements to the SHIPS Rapid Intensification Index - John Kaplan, NOAA/AOML/HRD, Miami, FL; and C. M. Rozoff, C. R. Sampson, J. P. Kossin, C. S. Velden, and M. DeMaria [poster available here]

Adopting Model Uncertainties for Tropical Cyclone Intensity Prediction Rosimar Rios-Berrios, University at Albany, State University of New York, Albany, NY; and T. Vukicevic and B. Tang

Real-time Verification of Passive Microwave Imagery-Based Statistical Models of Tropical Cyclone Rapid Intensification - Christopher M. Rozoff, CIMSS/Univ. of Wisconsin, Madison, WI; and C. S. Velden, J. Kaplan, A. Wimmers, and J. P. Kossin

Diurnal Pulsing of Lightning in Strong Tropical Cyclones - Stephanie N. Stevenson, University at Albany – State University of New York, Albany, NY; and K. L. Corbosiero and J. P. Dunion

Observed Hurricane Wind Speed Asymmetries and Relationships to Motion and Environmental Shear - Eric Uhlhorn, NOAA/AOML, Miami, FL; and B. W. KlotzT. Vukicevic, P. Reasor, and R. F. Rogers