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TRMM 3-Hourly 0.25 deg. TRMM and Other-GPI Calibration Rainfall Data

Entry ID: GES_DISC_TRMM_3B42_V7

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Summary

Abstract: The Tropical Rainfall Measuring Mission (TRMM) is a joint U.S.-Japan satellite mission to monitor tropical and subtropical precipitation and to estimate its associated latent heating. TRMM was successfully launched on November 27, at 4:27 PM (EST) from the Tanegashima Space Center in Japan.

The rainfall measuring instruments on the TRMM satellite include the Precipitation Radar (PR), an ... electronically scanning radar operating at 13.8 GHz; TRMM Microwave Image (TMI), a nine-channel passive microwave radiometer; and Visible and Infrared Scanner (VIRS), a five-channel visible/infrared radiometer.

The purpose of the 3B42 algorithm is to produce TRMM-adjusted merged-infrared (IR) precipitation rate (in mm/hr) and root-mean-square (RMS) precipitation-error estimates. The algorithm combines multiple independent precipitation estimates from the TMI, Advanced Microwave Scanning Radiometer for Earth Observing Systems (AMSR-E), Special Sensor Microwave Imager (SSMI), Special Sensor Microwave Imager/Sounder (SSMIS), Advanced Microwave Sounding Unit (AMSU), Microwave Humidity Sounder (MHS), and microwave-adjusted merged geo-infrared (IR). All input microwave data are intercalibrated to TRMM Combined Instrument (TCI) precipitation estimates (TRMM product 3B31); the iIR estimates are computed using monthly matched microwave-IR histogram matching; then missing data in individual 3-hourly merged-microwave fields are filled with the IR estimates. After the preprocessing is complete, the 3-hourly multi-satellite fields are summed for the month and combined with the monthly accumulated Global Precipitation Climatology Centre (GPCC) rain gauge analysis using inverse-error-variance weighting to form a monthly best-estimate precipitation rate, which is TRMM Product 3B43. The final step is to scale all the 3-hourly estimates for the month to sum to the monthly value (for each gridbox separately). The final 3B42 precipitation (in mm/hr) estimates have a 3-hourly temporal resolution and a 0.25-degree by 0.25-degree spatial resolution. Spatial coverage extends from 50 degrees south to 50 degrees north latitude.

The data are stored in the Hierarchical Data Format (HDF), which includes both core and product specific metadata. The file size is about 0.74 MB (compressed).

Important Changes: After the initial Version 7 processing, it was discovered that AMSU data were neglected in the first retrospective processing of both the Version 7 TMPA (3B42/43) and TMPA-RT (3B40/41/42RT) data series, which created an important shortcoming in the inventory of microwave precipitation estimates used during 2000-2010. In addition, a coding error in the TMPA-RT replaced the occasional missings in product 3B42RT with zeros. Accordingly, both product series were retrospectively processed again. The main impact in both series was to improve the fine-scale patterns of precipitation during 2000-2010 (and for 3B4xRT into late 2012). Averages over progressively larger time/space scales should be progressively less affected. [This is the reason the lack of AMSU went undiscovered; the merger system copes very reasonably with missing data.] Nonetheless, users are urged to switch to the newest Version 7 data sets. The newest runs may be identified by the file names: V.7 3B42/43 suffix of "7A.HDF" for January 2000 - September 2010 V.7 3B4xRT suffix of "7R2.bin" for 1 March 2000 - 6 November 2012 It continues to be the case that the Version 7 3B42/43 is some 4% higher than the calibrating data set (2B31) over oceans, which is still under study. However, the initial conclusion is that it results from the sampling mismatch between the (very sparse) TCI and the (much denser) microwave constellation. At the large scales this offset seems to be nearly a proportional constant.

TRMM Product FAQ: http://disc.sci.gsfc.nasa.gov/additional/faq/precipitation_faq.shtml

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Description: OPeNDAP Earth Science Data TRMM 3B42.

Multimedia Sample

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Caption: 3B42 TRMM and others combined 3 hour accumulated surface rainfall

Geographic Coverage

(Click for Interactive Map)

Spatial coordinates

N: 50.0

S: -50.0

E: 180.0

W: -180.0

Data Set Citation

Dataset Originator/Creator: Tropical Rainfall Measurement Mission Project (TRMM)

Dataset Title: TRMM 3-Hourly 0.25 deg. TRMM and Other-GPI Calibration Rainfall Data

Version: 7

Online Resource: http://mirador.gsfc.nasa.gov/cgi-bin/mirador/presentNavigation.pl?t...

Temporal Coverage

Start Date: 2003-01-18

Stop Date: 2003-10-24

Location Keywords

GEOGRAPHIC REGION > GLOBAL

Data Resolution

Latitude Resolution: 1km
Longitude Resolution: 1km

Science Keywords

ATMOSPHERE > CLOUDS > CLOUD PROPERTIES > CLOUD FREQUENCY

ISO Topic Category

CLIMATOLOGY/METEOROLOGY/ATMOSPHERE

OCEANS

IMAGERY/BASE MAPS/EARTH COVER

Platform

ADEOS-II > Advanced Earth Observing Satellite-II

Instrument

GLI > Global Imager

Ancillary Keywords

ADEOS-2

SATELLITE

Originating Center

JAXA

Data Center

Earth Observation Center, Japan Aerospace Exploration Agency, Japan

Data Center URL: http://www.eorc.jaxa.jp/en/index.html

Data Center Personnel
Name: JAXA EOC USER SERVICES Phone: +81-49-298-1262 Fax: N/A Email: orderdesk at eoc.jaxa.jp Contact Address: Japan Aerospace Exploration Agency (JAXA) Earth Observation Center City: 1401 NUMANOUE OHASHI HATOYAMA-MACHI Province or State: HIKI-GUN SAITAMA-KEN Postal Code: 350-0302 Country: JAPAN

Distribution

Distribution Media: DVD-R

Distribution Media: Online Download

Creation and Review Dates

DIF Creation Date: 2012-08-21

Last DIF Revision Date: 2012-09-10

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