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Model Initialization Using Single-Doppler Retrieved Fields Obtained From WSR-88D Level-II Data

Model Initialization Using Single-Doppler Retrieved Fields Obtained From WSR-88D Level-II Data. Steve Weygandt, Alan Shapiro, Keith Brewster, Jason Levit, Kelvin Droegemeier Center for Analysis and Prediction of Storms, Coastal Meteorology Research Project, University of Oklahoma. BACKGROUND.

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Model Initialization Using Single-Doppler Retrieved Fields Obtained From WSR-88D Level-II Data

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  1. Model Initialization Using Single-Doppler Retrieved Fields Obtained From WSR-88D Level-II Data Steve Weygandt, Alan Shapiro, Keith Brewster, Jason Levit, Kelvin DroegemeierCenter for Analysis and Prediction of Storms, Coastal Meteorology Research Project, University of Oklahoma

  2. BACKGROUND • Single-Doppler Parameter Retrieval developed to explicitly initialize ongoing convection in a high-resolution model using WSR-88D wideband data • Research and quasi-operational testing ongoing • Issues related to operational implementation: • Retrieval sensitivity to storm and data characteristics? • Predictability limits for storm-scale phenomena? • Computer power for real-time retrieval/prediction? • Band-width for rapid transfer of level-II data?

  3. Results From Four Cases • 2 km forecast of 24 August 1994 MCS (Wichita) (data sensitivity study by J. Zong) • 9 km test on 4 December 1998 squall line (Oklahoma City) • 9 km test on 5 April 1999 squall line (Oklahoma City, Dallas, Fort Smith) • 3 km test on 3 May 1999 OKC tornado outbreak (Oklahoma City) • Oklahoma Mesonet, GOES Satellite, Wind Profiler, Surface METARS, MDCRS Commercial Aircraft, NIDS Level-III Radar Data • Full model physics including radiation, ice microphysics, terrain, surface energy budget

  4. 0100 UTC 4 DEC 1999 KTLX Refl. W E *

  5. Initial 700 mb VERT VEL (Dx = 9km) * * * RETR NO RETR Wmax = 0.65 m/s Wmax = 0.26 m/s

  6. 1-hr Model Forecast Surface Refl. * * * RETR NO RETR

  7. 5 April 1999 - Level-II Data with Retrieval vs. NIDS Level-III Data 12 Z Obs Reflectivity Initial 700 mb Vertical Velocity Using NIDS Initial 700 mb Vertical Velocity with Level-II Data and Retrieval Wmax = 0.09 m/s Wmax = 0.33 m/s

  8. 5 April 1999 - Level-II Data with Retrieval vs. NIDS Level-III Data 15 Z Obs Reflectivity 3 Hour ARPS Refl Forecast (9 km) Using Level II Data and Retrieval Valid 15Z 3 Hour ARPS Refl Forecast (9 km) Using NIDS Data Valid 15Z

  9. 3 May 1999 Tornadoes Level-II Data and Retrieval Single-Doppler Retrieved Fields at 2200 UTC (Dx = 3 km) Z=5 km Reflectivity and Vertical Velocity Z=5 km Reflectivity and Pert. Horizontal Winds

  10. 3 May 1999 Tornadoes Level-II Data and Retrieval 1 Hour Model Prediction at 2300 UTC Z=2 km Reflectivity and Horizontal Winds Observed Reflectivity (dBZ)

  11. 3 May 1999 Tornadoes Level-II Data and Retrieval 1.5 Hour Model Prediction at 2330 UTC Z=2 km Reflectivity and Horizontal Winds Observed Reflectivity (dBZ)

  12. 3 May 1999 Tornadoes Level-II Data and Retrieval 2 Hour Model Prediction at 0000 UTC 4 May Z=2 km Reflectivity and Horizontal Winds Observed Reflectivity (dBZ)

  13. FUTURE • Detailed analysis of forecast impact from Single-Doppler retrieved fields • Real-time testing of retrieval package • Continued development of retrieval algorithm • Basic storm-scale sensitivity/predictability experiments

  14. Shapiro’s Two-Scalar Single-Doppler Velocity Retrieval Assume reflectivity is conserved: Assume velocity field satisfies a velocity constraint: where U and V are constant pattern translation components following Gal-Chen (1982)

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