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GRACE Data Spreads Awareness of Groundwater Levels

SciTechDaily Mars 2012

The depletion of groundwater from large aquifers due to drought and human activities affects gravity enough to provide a signal that GRACE can measure, in concert with other remote sensing data

GRACE Data Spreads Awareness of Groundwater Levels

SciTechDaily 23/03/2012

To help bring awareness to the importance of Earth’s groundwater, a new map showing the world’s groundwater supplies has been created in part from data acquired by the NASA/German Aerospace Center and the Climate Experiment (GRACE) mission.

To highlight declines in the world’s groundwater supplies, a new visualization of Earth’s groundwater reserves, created in part with space data from the joint NASA/German Aerospace Center (DLR) Gravity Recovery and Climate Experiment (GRACE) mission, debuted on New York’s Times Square on March 22, International World Water Day.

Groundwater is a critical, but often overlooked, natural resource. According to a U.N. report, more than 1.5 billion people around the world depend on groundwater for their drinking water. It comes from the natural percolation of precipitation and other surface waters down through Earth’s soil and rock, accumulating in cavities and layers of porous rock, gravel, sand or clay. Groundwater levels respond slowly to changes in weather and can take months or years to replenish once pumped for irrigation or other uses.

Famiglietti’s analyses show that groundwater is being depleted at alarming rates in many of the world’s major aquifers. “The GRACE data set is exciting, because it gives us the first global pictures of Earth’s changing freshwater,” he said.

The depletion of groundwater from large aquifers due to drought and human activities affects gravity enough to provide a signal that GRACE can measure, in concert with other remote sensing data. After accounting for other mass variations, such changes in gravity can be translated into an equivalent change in water. GRACE has been used to detect major depletion of groundwater in northern India, California’s Central Valley and elsewhere around the globe.

Groundwater levels are monitored by local sensors as well as from space with GRACE, but the data are formatted for expert hydrologists, rather than concerned citizens. Underground and out of sight, the public lacks a clear indicator of changing groundwater levels. By using the GRACE satellite data, HeadsUP ! offered designers the chance to visualize the water under the surface of Earth, as “seen” from space.

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Page publiée le 12 avril 2012, mise à jour le 20 novembre 2012