TRMM_2A55UW: 3D Radar Reflectivity for Satellite Rainfall Validation

University of Washington's TRMM Ground Validation product 2A55UW provides a 3D cartesian grid of radar reflectivity and velocity, specifically for validating satellite rainfall estimates. This dataset is generated only for volumes of interest, defined as those within 15 minutes of satellite overpass or with significant rainfall rates. It supports the comparison of ground-based measurements from four primary sites with data from the Tropical Rainfall Measuring Mission (TRMM) satellite.

Use Cases

• Validating TRMM satellite rainfall estimates based on ground-based radar and disdrometer data.
• Analyzing the 3D structure of precipitation events using 2km horizontal and 1km vertical resolution grids.
• Studying drop size distributions at key validation sites like Kwajalein and Melbourne.
• Comparing rainfall characteristics across different geographic regions (e.g., Darwin, Houston, Kwajalein, Melbourne).

Strengths

• Data is quality-controlled as part of the TRMM Ground Validation effort, which uses multiple instrument types (radar, rain gauges, disdrometers).
• Provides specific 3D spatial resolution (2km horizontal, 1km vertical) over a defined 150x150km horizontal and 2-15km vertical extent.
• Dataset is hosted on multiple authoritative platforms (Data.gov, NASA Earthdata), indicating established use and importance.

Limitations

• Column names and specific data schema are not provided in any source description.
• Conflicting metadata exists: the last update date is listed as 2026-04-10 on Data.gov (a future date suggesting a system error) and 2003-12-31 on NASA Earthdata.
• The dataset is not created for every radar volume, only for 'volumes of interest', which may limit temporal continuity.

Provenance

Source

National Aeronautics and Space Administration (NASA), University of Washington TRMM Ground Validation program.

Collection Method

Data collected from ground-based radar, rain gauges, and disdrometers at primary validation sites, processed through NCAR SPRINT interpolation.

Freshness

2003-12-31

Geography

Four primary ground validation sites: Darwin, Australia; Houston, Texas; Kwajalein, Republic of the Marshall Islands; Melbourne, Florida. Additional measurements at NASA Wallops Flight Facility.