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Overview of TRMM Ground Validation

Overview of TRMM Ground Validation. Robert F. Adler & David B. Wolff NASA/GSFC. Overview. Overview of TRMM Ground Validation Description of Primary TRMM GV Sites Comparing GV & TRMM Rain Intensities Other Activities Greater NASA Wallops GV Network

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Overview of TRMM Ground Validation

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  1. Overview of TRMM Ground Validation Robert F. Adler & David B. Wolff NASA/GSFC

  2. Overview • Overview of TRMM Ground Validation • Description of Primary TRMM GV Sites • Comparing GV & TRMM Rain Intensities • Other Activities • Greater NASA Wallops GV Network • Florida Keys as a complementary GV site for TRMM • TRMM 3B42 vs. Atoll Gauge Data (Huffman et al.) • MELB PR/GV Comparisons (Meneghini et al)

  3. TRMM GV Processing Status

  4. KWAJ: Kwajalein Atoll, RMI KPOL: S-band dual-pol 10 cm radar. Seven gauge sites (co-located gauges at each site). X-array gauge site at Roi Namur Disdrometers on Kwajalein and Roi Namur islands.

  5. MELB: Melbourne, Florida WSR-88D 10 cm Doppler radar Multiple gauge networks (STJ, SFWMD, KSC)

  6. DARW: Darwin, Northern Territory, Australia CPOL: C-band dual-pol 10 cm radar. 30+ gauge sites Significantly enhanced by BMRC support

  7. HSTN: Houston, Texas WSR-88D Radar located in League City 150+ gauges operated by the Harris County Office of Emergency Management

  8. GV Data Processing • The NASA TRMM Office is responsible for collecting, processing and distributing GV data products • Level I: 1B-51, 1C-51 • Level II: 2A-53, 2A-54, 2A-55, 2A-56 • Level III: 3A-54 • Data is processed using the Ground Validation System (GVS) and the Radar Software Library (RSL), both of which are available on the web. http://trmm-fc.gsfc.nasa.gov

  9. Level I GV Products • 1B-51 • All sites: radar reflectivity (DZ) and radial velocity (VR), polar coordinates • Darwin: Also ZDR • Kwajalein: Also ZDR and KDP • Data truncated at 230 km • All volume scans (VOS) packaged into hourly granules in HDF format • 1C-51 • Observed radar reflectivity + corrective mask • Maximum range 150 km

  10. Radar Data Quality Control • Radar • Remove non-precipitating echoes that may impact quality of higher level products • Anomalous propagation (AP), insects, birds, chaff, wildfires • Algorithm originally developed by Rosenfeld et al 1995. • 8 adjustable parameters • Manually intensive -> algorithm not fully automated except at Kwajalein

  11. Gauge Data Quality Control • Gauge • Fully automated algorithm (Amitai et al. 2000) • Applied to the combined radar and rain gauge data to determine which rain gauges (on a monthly scale) are unreliable for the purposes of Ze-R development. • If a gauge is considered unreliable, then all data for that month and gauge/(radar window) are ignored in Ze-R development.

  12. Level II GV Products • 2A-52i: Rain existence • 2A-53: Instantaneous rain rate† • 2A-54: Stratiform/convective rain type† • 2A-55: Three-dimensional reflectivity†† †151 x 151 grid at 2 km horizontal resolution † †151 x 151 x 13 grid at 1.5 km vertical resolution

  13. Level III GV Products • 3A-53: Five day (pentad) rainfall map † • 3A-54: Monthly rainfall map † • 3A-55: Three dimensional structure with vertical profiles †151 x 151 grid at 2 km horizontal resolution

  14. Level I & II Processing Flowchart

  15. Applications Using TRMM GV data

  16. V6r Biases - KWAJ 1999-2004

  17. V6r Monthly Means - KWAJ 1999-2004

  18. Greater Wallops Island GV Network

  19. Wallops Island Gauge/Disdrometer Radar “Farm”

  20. Florida Keys as a Complimentary GV Site for TRMM • The TRMM Project has conducted field activities during August-September 2001-2003. • 2001: Keys Area Microphysics Program (KAMP/CAMEX-III) • 2002: Keys Area Precipitation Project (KAPP 2002, TRMM Project) • 2003: Keys Area Precipitation Project (KAPP 2003, TRMM Project)

  21. Keys Gauge Network

  22. TRMM Multi-Satellite Precipitation Analysis • Huffman et al. 2005 • The MPA primarily depends on input from two different sets of sensors. • Passive microwave data • Low-Earth-orbit (LEO) satellites • TMI, SSM/I, AMSR-E (Aqua) AMSU-B (NOAA) • Infrared (IR) data • geosynchronous-Earth-orbit (GEO) satellites

  23. TRMM MPA Early Results - Atolls

  24. Radar Measurements Meneghini et al.

  25. PR (v6) vs WSR-88D at h=1.5 km Scatter Plots of Mean Reflectivity

  26. PR (v5) vs WSR-88D at h=1.5 km Scatter Plots of Mean Reflectivity

  27. Scatter Plots of Mean Rain

  28. Summary and Plans for the Future • TRMM GV data processing is fully up-to-date. • Routine comparisons between GV and TRMM estimates is now underway. • Utilization of other data sets/analyses (atolls, buoys, research gauge networks) for comparison with TRMM continues • Studying sites and techniques to improve overall validation program for TRMM, for the near future (AMSR, multi-satellite), and for transitioning into GPM

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