The Global Precipitation Measurement (GPM) Mission: An Overview

The Global Precipitation Measurement (GPM) Mission is an international satellite mission that uses an advanced precipitation radar with a constellation of passive microwave radiometers to improve the accuracy, sampling, and coverage of global precipitation estimates. It is a science mission with integrated applications goals focusing on (1) advancing the knowledge of the global water/energy cycle variability and freshwater availability and (2) improving weather, climate, and hydrological prediction capabilities.

The GPM Mission is currently a partnership between NASA and the Japanese Aerospace Exploration Agency (JAXA), with opportunities for additional domestic and international partners in providing constellation satellites and ground validation activities. The GPM Core satellite builds on the heritage of the highly successful Tropical Rainfall Measuring Mission (TRMM) in several ways: It carries a JAXA-provided dual-frequency precipitation radar and a NASA-provided microwave radiometer with high-frequency capabilities for light rain and frozen precipitation estimates, and it covers most of the globe from a low-Earth orbit inclined at 65°. Upon its launch in the 2010 timeframe, the GPM Core will serve as a precipitation physics laboratory and as a calibration system for improving precipitation estimates by a heterogeneous constellation of dedicated and satellite-of-opportunity microwave radiometers. NASA also plans to provide a “wild card” constellation satellite that carries a copy of the radiometer carried on the GPM Core, and which will be placed in an orbit that maximizes the coverage and sampling of the constellation.

An overview of the GPM mission concept, instrument capabilities, ground validation plans, expected scientific and societal benefits, and mission status will be presented.