Measuring Rain and Snow from Space

Rain and snow observations are about to become more sophisticated thanks to a new satellite cruising 253 miles above Earth.

Global Precipitation Measurement (GPM) is an international satellite mission to provide worldwide observations of rain and snow every three hours. NASA and the Japanese Aerospace Exploration Agency (JAXA) launched the GPM Core Observatory satellite on February 27  from Tanegashima Space Center in Japan. The GPM Core Observatory builds on the Tropical Rainfall Measuring Mission (TRMM, launched 1997), which measures rainfall in the tropics, by extending measurements to cover the globe from the Antarctic Circle to the Arctic Circle.

GPM will help provide uniform, global observations of rain and snow that are difficult to obtain from ground measurements. Data from the GPM Core Observatory will help improve our understanding of the water cycle and its links to climate change. Data will also help improve hurricane monitoring and prediction, enhance weather and climate computer models, help improve forecasting of floods, droughts and landslides, contribute to better agricultural crop forecasting and help scientists better predict changes in fresh water supplies.

Fast facts about the GPM Core Observatory:

  • It is the largest satellite assembled and tested at NASA Goddard Space Flight Center.
  • It flies at an altitude of 253 miles, covering an area spanning from the Antarctic Circle to the Arctic Circle.
  • It  measures rain and snow using two instruments, the GPM Microwave Imager (GMI), which detects different kinds of precipitation, and the Dual-frequency Precipitation Radar (DPR), which  provides information about the three-dimensional structure of precipitation. Learn more about these instruments.

Check out this video from NASA to learn more about the GPM Mission and its goals.

(Sources: “NASA, JAXA Prepare Rain and Snow Satellite for Launch,”; Global Precipitation Measurement,

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