Gravity Field Measurements Can Track Climate Change, Scientists Say
An international team of scientists has shown that precise measurements of Earth's changing gravity field can effectively monitor changes in the planet's climate and weather, says a National Aeronautics and Space Administration (NASA) press release.The finding comes from more than a year's worth of data from the Gravity Recovery and Climate Experiment, or Grace, a two-spacecraft, joint partnership of NASA and the German Aerospace Center.Results published in the journal Science show that the researchers could estimate monthly changes in the distribution of water and ice masses by measuring changes in Earth's gravity field. The Grace data measured the weight of up to 10 centimeters of groundwater accumulations from heavy tropical rains, particularly in the Amazon basin and Southeast Asia. Smaller signals caused by changes in ocean circulation were also visible."The Grace gravity measurements will be combined with water models to sketch an exceptionally accurate picture of water distribution around the globe. Together with other NASA spacecraft, Grace will help scientists better understand the global water cycle and its changes," said Michael Watkins, Grace project scientist at NASA's Jet Propulsion Laboratory in Pasadena, California.Launched in March 2002, Grace tracks changes in Earth's gravity field. Grace senses minute variations in gravitational pull from local changes in Earth's mass. Grace maps these variations from month to month, following changes imposed by the seasons, weather patterns and short-term climate change.Understanding how Earth's mass varies over time is important for studying changes in global sea level, polar ice mass, deep ocean currents, and depletion and recharge of continental aquifers.Grace monthly maps are up to 100 times more accurate than existing maps, substantially improving the accuracy of many techniques that oceanographers, hydrologists, glaciologists, geologists and other scientists use to study climate-influencing phenomena.