Rain and Snow Satellite Set to Launch
Feb. 26, 2014: As Arthur C. Clarke once remarked, "How inappropriate to call this planet Earth when it is quite clearly Ocean."
Indeed, Earth is a water world. The dry land most of us call home covers less than a third of the planet’s surface. Water moves around Earth with a circulation as complex as that of the human body. Evaporation, condensation, and precipitation transport warmth and moisture from place to place, sustaining life and setting the stage for weather and climate.
"The water-cycle, so familiar to all school-age young scientists, is one of the most dynamic and important elements in our studies of Earth," says John Grunsfeld, associate administrator for NASA's Science Mission Directorate in Washington DC. "We're about to launch a new satellite that gives us critical information about how the water-cycle works."
It's called the Global Precipitation Measurement Core Observatory--or "GPM" for short. Built by NASA and JAXA, the Japan Aerospace Exploration Agency, the satellite is scheduled to launch on Feb. 27th at 1 pm EST from the Tanegashima Space Center in Japan.
GPM will fly 253 miles above Earth in an orbit inclined 65-degrees to the equator. This orbit allows the satellite to monitor precipitation all the way from the Arctic to the Antarctic circles. Working with a network of other satellites--some already in orbit and some planned for the future--GPM can measure rain and snow every three hours anywhere on the globe.
"The kind of data we'll get from the GPM network is unprecedented," says Gail Skofronick-Jackson, GPM project scientist at Goddard. "We'll be able to observe detailed characteristics of rain and snow systems that are extremely important for improving weather and climate forecasts."
Normal operations will begin about 60 days after launch. Data will be downlinked through NASA's Tracking and Data Relay Satellite System to NASA's Precipitation Processing Center in Greenbelt, Md., where it will be processed and distributed over the Internet.
GPM carries two instruments to measure rain and snowfall: a Dual-frequency Precipitation Radar and the GPM Microwave Imager. Compared to instruments flown on previous Earth science satellites, GPM’s precipitation radar and microwave imager can see deeper into clouds and detect smaller particles of rain, ice and snow. The radar will be able to form 3D profiles of precipitation, revealing the inner workings of cloudy storm systems. The microwave imager will measure not only heavy and moderate rain, as other satellites do, but also light rain and snow—two forms of precipitation important over mountain ranges and high-latitude sites in North America, Europe and Asia.
What we learn from GPM network, concludes Grunsfeld, "will help us cope with future extreme weather events and manage fresh water resources" in a changing world.
Make that water world.
Global Precipitation Measurement Core Observatory -- home page
JAXA -- home page