Global rainfall prior to the Launch of Global Precipitation Measurement (GPM) Satellite

The Global Precipitation Measurement, or GPM, mission will use an international constellation of satellites to study global rain, snow and ice to better understand our climate, weather, and hydrometeorological processes. We cannot understand the water and energy cycle or predict weather and climate without an accurate knowledge of the intensity and distribution of global precipitation. Measurement of various aspects of precipitation (e.g. distribution, amount, rates, and the associated heat release) represents one of the most challenging research problems in Earth science. Yet, accurate global precipitation measurements will benefit weather, climate, hydro-meteorological, and applications communities alike. The concept of Global Precipitation Measurement (GPM) is NASA's response to the need for accurate global precipitation measurement.