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A Multi-Faceted Examination of the Extratropical Transition of Tropical Cyclones

A Multi-Faceted Examination of the Extratropical Transition of Tropical Cyclones. Tuesday, July 19, 2005 2 pm. Steve Guimond ONR Intern FSU/COAPS. Overview of Extratropical Transition (ET). symmetric,warm-core,non-frontal,barotropic GOES-12 1 km VIS

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A Multi-Faceted Examination of the Extratropical Transition of Tropical Cyclones

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  1. A Multi-Faceted Examination of the Extratropical Transition of Tropical Cyclones Tuesday, July 19, 2005 2 pm Steve Guimond ONR Intern FSU/COAPS

  2. Overview of Extratropical Transition (ET) symmetric,warm-core,non-frontal,barotropic GOES-12 1 km VIS Hurricane Karl 20 Sep 2004 1215Z 17N Typhoon Sonca 25 Apr 2005 0302Z 16N www.nnvl.noaa.gov

  3. Overview of Extratropical Transition (ET) asymmetric,cold-core,frontal,baroclinic GOES-12 1 km VIS GOES-9 4 km IR Hurricane Karl 24 Sep 2004 1215Z 40N Typhoon Sonca 25 Apr 2005 0302Z 21N www.nnvl.noaa.gov

  4. Tracking TC Structure: Cyclone Phase Space (Dr. Robert Hart FSU)

  5. Who Cares? Why Is This Important? • ET can produce: • Continuation of high winds with wind field expansion • Large ocean swell • Extreme rainfall (intensity and accumulation) • Rapid track accelerations • Forecasting Challenges • Predicting track,intensity and rainfall • Warning for high winds,heavy seas and flooding • Threat to Naval operations in various sub-tropical ocean basins

  6. How Can I Help Solve The Problem? New Approaches to Analyzing ET Focus: Quantitative Precipitation Forecasting (QPF) • Multi-Satellite Blended Precipitation Products • Mapping Cyclone Structural Phase from Satellite Perspective • Algorithm to Compute CAPE from AMSU/HIRS for Convective Rainfall Predictive Purposes Master’s Thesis • Computing Moisture Budget • Describing Dynamical Forcings from Phase Space

  7. Model Moisture Evaluation: Hurricane Karl • ECMWF 1.125° vs. NOGAPS QUASI 1.0° • Mean 400-500 hPa Relative Humidities • Compared to GOES-12 WV(ch 3) 4 km • Weighting Function Peaks in ~400-500 hPa Layer • Purpose: To find model that describes evolution of ET signatures more realistically

  8. ECMWF 1.125 ° NOGAPS ~1.0 °

  9. ECMWF 1.125 ° NOGAPS ~1.0 °

  10. Isentropic Ertel Potential Vorticity Hurricane Karl 2004 Explains interaction and response of TC from movement into a baroclinic environment

  11. Isentropic Ertel Potential Vorticity Animation Typhoon Sonca 2005 Early Season Case: Storm Sheared Apart By Sub-Tropical Jet

  12. Multi-Satellite Blended Precipitation Products • Buffet of Passive Microwave Sensors (“constellation”) • TRMM TMI/PR • F-13/14/15 DMSP/SSMI • NOAA-15/16/17 AMSU-B • EOS AMSR-E • Utilize rapid time capability of geo-IR to calibrate the IR obs between gaps in constellation Result ? • High quality precip on dense space and time scales • NASA vs. NRL: NRL smaller error!!

  13. Blended Satellite Precipitation NRLB:Hurricane Karl Mean 3 hourly rainrate

  14. Blended Satellite Precipitation NRLB:Typhoon Sonca 2005 Mean 3 hourly rainrate

  15. Precipitation Evolution Analysis Techniques • Divide storm into annuli • Examine mean precipitation change (intensity and accumulation) vs. time and distance from TC center • Serve as risk assessment tool for ET precipitation enhancement and flooding

  16. Mapping Cyclone Structural Phase:Satellite Perspective • TRMM PR Bright Band Heights proxy for warm/cold core structure • Bright Band = distinct radar signal created by frozen hydrometeors falling through storm melting layer • Stratiform precipitation typically associated with convective cells • Retrieve melting layer heights along ET track produce satellite derived cyclone phase

  17. Test Case: Typhoon Meari 2004 • TRMM PR STATS • 4 km horizontal resolution • 250 m vertical resolution • 220 km swath width • Coverage: 40°N/S • 100 along track scans/minute • 49 across track rays/scan AMSU AMSU

  18. TRMM PR Vertical Cross Section Animation • Things to look for: • Fluctuations in Convective Cloud Heights • Mirrors intensity change • (2) Development of Outer Core/Asymmetric Precipitation • ET Signature • (3) Changes to darker colors • Heavy precipitation;Higher dBZ values

  19. Zoomed Snapshots: Two Stages of Typhoon Meari Warm Core Cold Core

  20. A TRMM PR STRUCTURAL TRACK

  21. Features of CAPE algorithm • Soundings produced from retrievals of T and Q at each pixel of AMSU/HIRS • Mixed layer parcel • 100 hPa tropics;50 hPa mid-lats yields more accurate cloud base heights and CAPE (Craven et al. 2002) • Virtual temperature correction • Accounts for variable amount of moisture allowing use of dry gas constant when calculating density • Accounts for irregular soundings • Unrealistic tropopause levels • Parcel acquiring negative buoyancy

  22. Test Case: Hurricane KarlExamining Convective Precipitation Response to CAPE Trough approaching high CAPE

  23. TEST CASE: Hurricane Karl Potential for convective forecasting over various ocean basins and regions with sparse radiosonde networks TC Genesis Studies

  24. What to Take Away From this Seminar • Multi-satellite blended precipitation products useful for QPF studies • Explain ET rainfall enhancement • Blazing Trails: Never been done before with ET • Objective satellite cyclone phase • Shown to distinguish ET commencment from warm to cold core • Promise for future work • CAPE algorithm useful for convective precipitation forecasting • AMSU/HIRS derived soundings need work in upper levels

  25. MANY,MANY THANKS TO • Jeff Hawkins • Support for Internship;Insightful comments;Food and Beverage (pumpkin bread) • Joe Turk • Extensive knowledge of satellite precipitation;Making me spend 3+ hours retrieving TRMM data • Clay Blankenship and Ben Ruston • Retrievals for CAPE;support for coding issues • Kim Richardson • Computer assistance and book loans • Rob Wade • NOGAPS and GOES WV data Everyone who made my stay an enjoyable one!

  26. Thanks to Tom Lee for BIG SUR TRIP

  27. ECMWF 1.125 ° NOGAPS ~1.0 °

  28. ECMWF 1.125 ° NOGAPS ~1.0 °

  29. ECMWF 1.125 ° NOGAPS ~1.0 °

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