TRMM and Other Satellites Precipitation Product 3B42

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Abstract: This document provides basic information on 3B42, TRMM and Other Satellites Precipitation Product.The TRMM Multi-Satellite Precipitation Analysis (TMPA; computed at fine intervals as 3B-42) intercalibrates (to 2B31) and combines 2A-12, SSMI, AMSR and AMSU precipitation estimates (referred to as HQ). IR estimates from geostationary IR observations are made by calibrating the IR brightness temperatures to the HQ estimates. The 3B-42 estimates consist of the HQ where available and IR otherwise, all scaled to match the monthly satellite/rain gauge analyses in 3B-43.The output is precipitation for 0.25x0.25 degree grid boxes on the latitude band 50 ° N-S every 3 hours. For more details of the algorithm, go to
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Description: OPeNDAP Earth Science Data TRMM 3B42.
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Caption:  3B42 TRMM and others combined 3 hour accumulated surface rainfall
Geographic Coverage
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: 6
Online Resource:
Temporal Coverage
Start Date: 1997-12-31
Data Resolution
Latitude Resolution: 0.25 degree
Longitude Resolution: 0.25 degree
Horizontal Resolution Range: 10 km - < 50 km or approximately .09 degree - < .5 degree
Vertical Resolution: Surface
Temporal Resolution: 3-hourly
Temporal Resolution Range: Hourly - < Daily
Quality Adjusted GPI relative error estimates are provided for each 0.25 x 0.25 degree box. There are currently no known deficiencies in the 3B42 algorithm. The quality of the 3B42 product is highly sensitive to the quality of the input data: TRMM VIRS (product 1B01), TMI (product 2A12), and TRMM Combined Instrument (TCI) (product 3B31). If the quality of the input data is less than anticipated, then the quality of 3B42 will also be less.
Access Constraints None
Ancillary Keywords
Data Set Progress
Originating Center
Data Center
Goddard Earth Sciences Data and Information Services Center (formerly Goddard DAAC), Global Change Data Center, Earth Sciences Division, Science and Exploration Directorate, Goddard Space Flight Center, NASA Supplemental Info
Data Center URL:

Data Center Personnel
Phone: 301-614-5224
Fax: 301-614-5268
Email: gsfc-help-disc at
Contact Address:
Goddard Earth Sciences Data and Information Services Center
Code 610.2
NASA Goddard Space Flight Center
City: Greenbelt
Province or State: MD
Postal Code: 20771
Country: USA
Distribution Media: FTP
Distribution Size: file size: 3150 kb
Distribution Format: HDF
Fees: none
Phone: 301-614-6308
Fax: 301-614-5492
Email: George.J.Huffman at
Contact Address:
NASA Goddard Space Flight Center
Mailstop 612
City: Greenbelt
Province or State: MD
Postal Code: 20771
Country: USA
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Huffman, G.J., R.F. Adler, B. Rudolph, U. Schneider, and P. Keehn, 1995: Global Precipitation Estimates Based on a Technique for Combining Satellite-Based Estimates, Rain Gauge Analysis, and NWP Model Precipitation Information, J. Clim., 8, 1284-1295.

Huffman, G.J., 1997: Estimates of Root-Mean-Square Random Error for Finite Samples of Estimated Precipitation, J. Appl. Meteor., 1191-1201.

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Creation and Review Dates
DIF Creation Date: 2006-09-12
Last DIF Revision Date: 2014-05-02
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