NASA Builds Global Precipitation Measurement (GPM)

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. One of the critical components of the Earth's hydrological cycle is precipitation. Rainfall is essential for providing the fresh water that sustains life. Water cycling and the future availability of fresh water resources are immense societal concerns that impact every nation on Earth. It affects virtually every environmental issue. Solid forms of precipitation, such as snow and ice, frequently create hazardous conditions during winter storms. Heavy snowfalls severely disrupt transportation networks and temporarily paralyze local economies. Snowfall is also beneficial to many, as it provides the major source of fresh water during arid summer months in many mountainous regions. In the atmosphere, the condensation of water vapor into rain, and then rain into ice, releases vast quantifies of heat. The heat energy drives the wind systems of Earth's atmosphere, and powers violent storms such as hurricanes. In many respects, precipitation is truly the centerpiece of our planet's hydrological cycle, and understanding it is crucial to unraveling many of the uncertainties about Earth's climate.

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.