Satellite Serves a Thirstier World

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Satellite Serves a Thirstier World

How much fresh water is there on Earth? The answers come to us from a US-German satellite mission called GRACE. The GRACE satellites make a very precise measurement of changes in gravity below them as they pass over the Earth. 

Because water is less dense than rock or soil, it exerts less of a gravitational pull. Human beings can’t tell the difference, but GRACE can use it to detect the presence and depth of surface water and provide the first accurate global inventory of surface water.

Scientists are even finding ways to use satellites to find water hiding underground, which makes up as much as 40 percent of global supplies. Using a NASA radar satellite, a team from Stanford University recently achieved the first success in predicting the amount of groundwater beneath locations in California. 

Another research team has proven that areas of lower temperature on the ground signal supplies of water below that are close to the surface. Knowing where the groundwater is near the surface can make a life or death difference in developing nations. Laborers with hand tools can dig shallow wells, while deeper ones require costly mechanized drills.

Source: SSPI

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