The Tropical Rainfall Measuring Mission (TRMM), which flew from Novemer 2017 - June 2015, was a research satellite designed to improve our understanding of the distribution and variability of precipitation within the tropics as part of the water cycle in the current climate system. By covering the tropical and sub-tropical regions of the Earth, TRMM provided much needed information on rainfall and its associated heat release that helps to power the global atmospheric circulation that shapes both weather and climate. In coordination with other satellites in NASA's Earth Observing System, TRMM provided important precipitation information using several space-borne instruments to increase our understanding of the interactions between water vapor, clouds, and precipitation, that are central to regulating Earth's climate. Although the TRMM satellite is no longer in orbit, the TRMM-based multi-satellite TMPA dataset is still being produced and provides scientists a unified record of the worlds precipitation dating back to 1998, which is useful for climatological studies and computing precipitation anomalies.
Learn more: https://pmm.nasa.gov/trmm