TRMM 3B42 three_hourly merged rainfall

This dataset contains the output of TRMM Algorithm 3B42, which is to produce Tropical Rainfall Measuring Mission (TRMM) merged high quality (HQ)/infrared (IR) precipitation and root-mean-square (RMS) precipitation-error estimates.

The combined instrument rain calibration algorithm (3B-42) uses an optimal combination of 2B-31, 2A-12, SSMI, AMSR and AMSU precipitation estimates (referred to as HQ), to adjust IR estimates from geostationary IR observations. Near-global estimates are made by calibrating the IR brightness temperatures to the HQ estimates. The 3B-42 estimates are scaled to match the monthly rain gauge analyses used in 3B-43. The output is rainfall for 0.25x0.25 degree grid boxes every 3 hours. For more details of the algorithm, go to

IMPORTANT: After over 17 years of productive data gathering, the instruments on TRMM were turned off on April 8, 2015. The spacecraft re-entered the Earth's atmosphere on June 15, 2015, at 11:55 p.m. EDT, over the South Indian Ocean, according to the U.S. Strategic Command's Joint Functional Component Command for Space through the Joint Space Operations Center (JSpOC), and most of the spacecraft was expected to burn up in the atmosphere during its uncontrolled re-entry. The Tropical Rainfall Measuring Mission (TRMM), a joint mission of NASA and the Japan Aerospace Exploration Agency, was launched in 1997 to study rainfall for weather and climate research. The multi-satellite 3B42*/TMPA product will continue to be produced through mid-2017 - learn more about the transition from 3B42* to IMERG.
Read the TRMM end of mission frequently asked questions

Rain Rate (mm/hr), adjusted GPI relative error estimate (mm/hr)
Zonal180W to 180E by 0.25 deg
Meridional50S to 50N by 0.25 deg
Temporal V7: Jan 1, 1998 to Jun 30, 2017 by three hours
V6: Jan 1, 1998 to Feb 29, 2012 by three hours
Static? no
Volume36.85 Mbytes/day, 13.2 Gbytes/year
Acquired Aug 12, 2006 (Updated Sep 2017)
APDRC contact /
Supplements Readme_trmm_3B42_3hourly