TRMM Precipitation Radar Power and Reflectivity L1B 1.5 hours V7 (TRMM_1B21) at GES DISC

The TRMM Precipitation Radar (PR), the first of its kind in space, is an electronically scanning radar, operating at 13.8 GHz that measures the 3-D rainfall distribution over both land and ocean, and defines the layer depth of the precipitation.

The 1B21 calculates the received power at the PR receiver input point from the Level-0 count value which is linearly proportional to the logarithm of the PR receiver output power. To convert the count value to the input power, extensive internal calibrations are applied, which are mainly based upon the system model, temperature dependence of model parameters and many temperature sensors attached at various locations of the PR. Periodically the input-output characteristics are measured using an internal calibration loop for the IF unit and later receiver stages. To make an absolute calibration, an Active Radar Calibrator (ARC) is placed at Kansai Branch of CRL and overall system gain of the PR is being measured every 2 months. Using the transfer function based on the above internal and external calibrations, the PR received power is obtained. Note that the value assumes that the signal follows the Rayleigh fading, so if the fading characteristics of a scatter is different, a small bias error may occur (within 1 or 2 dB).

Changes in horizontal resolution resulting from the TRMM boost that occurred on 24 August 2001:

Pre-Boost (before 7 August 2001): Temporal Resolution: 91.5 min/orbit ~ 16 orbits/day; Swath Width: 215 km; Horizontal Resolution: 4.3 km

Post-Boost (after 24 August 2001): Temporal Resolution: 92.5 min/orbit ~ 16 orbits/day; Swath Width: 247 km; Horizontal Resolution: 5.0 km

Data and Resources

Additional Info

Field Value
Maintainer ANDREY SAVTCHENKO
Last Updated March 31, 2025, 15:27 (UTC)
Created March 31, 2025, 15:27 (UTC)
accessLevel public
bureauCode {026:00}
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catalog_@id https://data.nasa.gov/data.json
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catalog_describedBy https://project-open-data.cio.gov/v1.1/schema/catalog.json
citation Tropical Rainfall Measuring Mission (TRMM). 2011-07-01. TRMM_1B21. TRMM Precipitation Radar Power and Reflectivity L1B 1.5 hours V7. Greenbelt, MD. Archived by National Aeronautics and Space Administration, U.S. Government, Goddard Earth Sciences Data and Information Services Center (GES DISC). https://disc.gsfc.nasa.gov/datacollection/TRMM_1B21_7.html.
creator Tropical Rainfall Measuring Mission (TRMM)
graphic-preview-file https://docserver.gesdisc.eosdis.nasa.gov/public/project/Images/TRMM_1B21_7.png
harvest_object_id acea8544-2ac4-45e2-b4e7-8c49c555d455
harvest_source_id 61638e72-b36c-4866-9d28-551a3062f158
harvest_source_title DNG Legacy Data
identifier C1282110505-GES_DISC
issued 2011-07-01
landingPage https://cmr.earthdata.nasa.gov:443/search/concepts/C1282110505-GES_DISC.html
language {en-US}
metadata_type geospatial
modified 2016-04-20
programCode {026:001}
publisher NASA/GSFC/SED/ESD/GCDC/GESDISC
release-place Greenbelt, MD
resource-type Dataset
series-name TRMM_1B21
source_datajson_identifier true
source_hash 798735c5c7b116bb8c448ad560beaeda4723bd5a57a5ff37ec73c54f577e8340
source_schema_version 1.1
spatial -180.0 -38.0 180.0 38.0
temporal 1997-12-07T00:00:00Z/2015-04-01T23:59:59.999Z
theme {TRMM,geospatial}