Nine U.S. and international satellites will soon be united by the Global Precipitation Measurement (GPM) mission, a partnership co-led by NASA and the Japan Aerospace Exploration Agency (JAXA). NASA and JAXA will provide the GPM Core satellite to serve as a reference for precipitation measurements made by this constellation of satellites, which will be combined into a single global dataset continually refreshed every three hours.
 
While each partner satellite has its own mission objective, they all carry a type of instrument called a radiometer that measures radiated energy from rainfall and snowfall. The GPM Core satellite carries two instruments: a state-of-the-art radiometer called the GPM Microwave Imager (GMI) and the first space-borne Dual-frequency Precipitation Radar (DPR), which sees the 3D structure of falling rain and snow. The DPR and GMI work in concert to provide a unique database that will be used to improve the accuracy and consistency of measurements from all partner satellites, which will then be combined into the uniform global precipitation dataset.
 
In this animation the orbit paths of the partner satellites of the GPM constellation fill in blue as the instruments pass over Earth. Rainfall appears light blue for light rain, yellow for moderate, and red for heavy rain. Partner satellites are traced in green and purple, and the GPM Core is traced in red.
 
The GPM Core observatory is currently being built and tested at NASA's Goddard Space Flight Center in Greenbelt, Md. It is scheduled to launch from Tanegashima space center in Japan in early 2014.

Heat from the sun causes the molecule to evaporate from the ocean's surface. Once it evaporates, it is transported high in the atmosphere and condenses to form clouds. Clouds can move great distances and eventually the water molecule will fall as rain or snow. Ultimately, the water molecule arrives back where it started...at the ocean. 

Download this video in different formats from the NASA Goddard Scientific Visualization Studio

Water is all around us, and its importance to nearly every natural process on earth cannot be underestimated. The water cycle is the movement of water around the Earth in all its forms, from the ocean to the atmosphere, to snow, soil, aquifers, lakes, and streams on land, and ultimately backs to the ocean. This video explains what the water cycle is and how important it is to life on earth.

Engineers from the Japan Aerospace Exploration Agency (JAXA) and NASA Goddard Space Flight Center in Greenbelt, Md. oversee the arrival and unpacking of the dual-frequency Precipitation Radar (DPR) built by Japan for the Global Precipitation Measurement (GPM) mission's Core Observatory satellite. Comprised of two radars, the DPR is one of two instruments that will fly on the satellite, scheduled for launch in February 2014.

Video Text:

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Candace: The Dual Precipitation Radar, or DPR, made its way here from Japan. It was built by a company called NTSpace working for JAXA, the Japanese Space Agency.

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Art: The radars once they arrive here, they go through some processing, make sure during the shipment there was no damage done to the radars, even though we do have shock monitors on the boxes that we make sure there was no unexpected incidents happened during the transportation However, in spite of that, we still go through processing in house here, that we check, make sure functionally they're still working properly before they hand it over to NASA.

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Candace: The Dual Precipitation Radar, or DPR, has two parts: the first is the KaPR and the second is the KuPR, those are two different bands. And it provides simultaneous measurements in both of the bands, and it can be used to make combined products together with the GMI that allow the scientists to determine a lot more about precipitation, from rain, through snow, be it light or be it heavy, than they know today.

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