Wednesday, December 17, 2014

NASA Data Underscore Severity of California Drought

Trends in total water storage in California, Nevada and bordering states from NASA's Gravity Recovery and Climate Experiment (GRACE) satellite mission, September 2011 to September 2014. NASA scientists use these images to better quantify drought and its impact on water availability. Two-thirds of the measured losses were a result of groundwater depletion in California's Central Valley. (Credit: NASA JPL/Caltech) Click to Enlarge.
It will take about 11 trillion gallons of water (42 cubic kilometers) -- around 1.5 times the maximum volume of the largest U.S. reservoir -- to recover from California's continuing drought, according to a new analysis of NASA satellite data.

The finding was part of a sobering update on the state's drought made possible by space and airborne measurements and presented by NASA scientists Dec. 16 at the American Geophysical Union meeting in San Francisco.  Such data are giving scientists an unprecedented ability to identify key features of droughts, and can be used to inform water management decisions.

A team of scientists led by Jay Famiglietti of NASA's Jet Propulsion Laboratory in Pasadena, California, used data from NASA's Gravity Recovery and Climate Experiment (GRACE) satellites to develop the first-ever calculation of this kind -- the volume of water required to end an episode of drought.

Earlier this year, at the peak of California's current three-year drought, the team found that water storage in the state's Sacramento and San Joaquin river basins was 11 trillion gallons below normal seasonal levels.  Data collected since the launch of GRACE in 2002 show this deficit has increased steadily.

"Spaceborne and airborne measurements of Earth's changing shape, surface height and gravity field now allow us to measure and analyze key features of droughts better than ever before, including determining precisely when they begin and end and what their magnitude is at any moment in time," Famiglietti said.  "That's an incredible advance and something that would be impossible using only ground-based observations."

Read more at NASA Data Underscore Severity of California Drought

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