Measuring Ground Water from Space, 2002-2012

Measurements of ground water—rather than water on the surface—reveal the long-term effects of drought. These maps show ground water conditions in the U.S. compared to the long-term average from August 2002 to August 2012. (Map by Chris Poulsen, National Drought Mitigation Center, based on data from the GRACE science team.)

See the video at tinyurl.com/d3xmbn5 and learn more at http://earthobservatory.nasa.gov/Features/GRACEGroundwater/