Water- the world's most precious resource. All around the world, NASA's Global Precipitation Measurement mission is collected data on how much precipitation is falling to Earth. NASA has just released its newest and most comprehensive estimate of rain and snow covering nearly 20 years. Version 6 of NASA's IMERG -- the Integrated Multi-satellitE Retrievals for Global Precipitation Measurement (GPM) -- combines information from a constellation of satellites are operating in Earth orbit, at a given time, to estimate precipitation over the majority of the Earth's surface. This algorithm is particularly valuable over the majority of the Earth's surface that lacks precipitation-measuring instruments on the ground. What is new in Version 6 IMERG is that the algorithm can now fuse the early precipitation estimates collected in 2000-2014 during the operation of the TRMM satellite with more recent precipitation estimates collected during operation of the GPM satellite. The longer the record, the more valuable it is, as researchers and application developers will attest. TRMM and GPM are two satellites specially designed to provide the most reliable space-based estimates of precipitation, and both satellites are joint missions between NASA and the Japan Aerospace Exploration Agency (JAXA).
