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NASA uses GPS to find Sierra water weight

08 May 2014

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For the first time, NASA scientists have used GPS to find the total weight of winter snowpack and soil moisture in California's Sierra Nevada. The new results complement other satellite measurements and could provide a reality check for computer models used to estimate the state's water and snowpack.

A team led by Donald Argus of NASA's Jet Propulsion Laboratory, Pasadena, Calif., studied data from 1,069 GPS research sites in California, Nevada, Oregon and Washington, extending back to 2006. For each site, they averaged the difference in the ground level between 1 October (the end of the dry season) and 1 April of each year, when the snow is likely to be at its greatest weight. They then calculated how much water would be required to create the observed height changes.

On average, the yearly change in water weight between summer and winter in the Sierra Nevada of California and Klamath Mountains on the California-Oregon border was equal to 2 feet (0.6 metres) of water.

Source: National Aeronautics and Space Administration (NASA)

Image credit: Wikimedia Commons - Oregon GPS station