One of the great river basins of the Middle East, the Tigris-Euphrates—which flows through the so-called fertile crescent that gave birth to agriculture itself—is getting drier. A study in Water Resources Research, indicates that the region is losing water; 0.3 meters per year from 2006-09, at an an alarming rate.
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The nation's food supply may be vulnerable to rapid groundwater depletion from irrigated agriculture, according to a new study by researchers at The University of Texas at Austin and elsewhere.
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On March 17, 2002, NASA and the German Aerospace Center (DLR) launched the Gravity Recovery and Climate Experiment (GRACE), a novel space mission that has given scientists a new understanding of changes in Earth's natural systems. The identical twin GRACE spacecraft track changes in Earth's gravity field caused by local changes in Earth's mass caused by the seasons, weather patterns, short-term climate change and even large earthquakes. Grace has given us monthly measurements of Earth’s mean gravity field that are at least 100 times more precise than predecessors, substantially improving the accuracy of techniques used by oceanographers, hydrologists, glaciologists, geologists and climate scientists. The result has been an amazing array of breakthrough science. Here are some highlights.
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A new comprehensive University of Colorado-led study used gravity data from NASA's Grace mission to calculate how much Earth's melting land ice is adding to global sea level.
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Increasing freshwater on the U.S. and Canadian side of the Arctic from 2005 to 2008 is balanced by decreasing freshwater on the Russian side, so that on average the Arctic did not have more freshwater.
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The record-breaking drought in Texas that has fueled wildfires, decimated crops and forced cattle sales has also reduced groundwater levels in much of the state to the lowest levels in more than 60 years, according to new national maps produced by NASA using data from the NASA/German Aerospace Center Gravity Recovery and Climate Experiment (Grace) mission. The map are distributed by the National Drought Mitigation Center at the University of Nebraska-Lincoln.
The latest groundwater map, released on Nov. 29, shows large patches of maroon over eastern Texas, indicating severely depressed groundwater levels. The maps, publicly available on the Drought Center's website at http://go.unl.edu/mqk , are generated weekly by NASA's Goddard Space Flight Center in Greenbelt, Md., using Grace gravity field data calculated at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and the University of Texas Center for Space Research, Austin.
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Researchers at NASA's Goddard Space Flight Center have used this recent megaquake to show that the disturbances of satellite orbits can be used to independently estimate the magnitude and location of earthquakes, along with estimates based on surface seismographs and GPS measurements.
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NASA's GRACE and Jason satellites reveal how seasonal variations in Earth's water cycle contributes to rising, and sometimes falling, sea level.
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GRACE scientists used temporal gravity variations from GRACE to investigate changes in a 34?year time series of Earth’s oblateness observed by satellite laser ranging (SLR). They used 2002–2010 GRACE data to compute the effects of Greenland and Antarctic ice mass variations on oblateness. Their combined effect on the oblateness trend during the GRACE agrees well with the glacial isostatic adjustment (GIA)?corrected SLR oblateness trend over the same time period. The results suggest that at least since 2002, ice loss from Greenland and Antarctica has been the dominant contributor to this current trend, which apparently began sometime in the 1990s.
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The GRACE mission launched on March 17, 2002 from Plesetsk in Northern Russia, beginning a mission to make precise measurements of Earth's gravity field. Nine years later GRACE continues to unravel global climatic questions by providing and invaluable data set for a better understanding of ocean surface currents and heat transport, measuring changes in sea-floor pressure, watching the mass of the oceans change, and monitoring changes in the storage of water and snow on the continents.
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Researchers used data from the GRACE mission to estimate that California's Central Valley lost 20.3 cubic kilometers (16.4 million acre feet) of water between October 2003 and March 2010--a volume equal to 63 percent of the capacity of Lake Mead, the nation's largest reservoir. Most of that depletion occurred between April 2006 and March 2010, a period of drought when farmers pumped more groundwater to compensate for less rainfall and cutbacks in surface water deliveries to irrigators.
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The Greenland and Antarctic ice sheets are losing mass at an accelerating pace, according to a new NASA-funded satellite study. The findings of the study -- the longest to date of changes in polar ice sheet mass -- suggest these ice sheets are overtaking ice loss from Earth's mountain glaciers and ice caps to become the dominant contributor to global sea level rise, much sooner than model forecasts have predicted.
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Scientists from the German GFZ and French LEGOS/GOHS and CNES have jointly analyzed gravity data from GRACE, altimetry data and precipitation measurements over the Great Lakes region of East Africa to observe variability in terrestrial water storage, lake water volume and rainfall. Variability at interannual time scales, with a minimum in late 2005, followed by a rise in 2006 to 2007 is evident.
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The coding error previously reported has been fixed, the corrected GIA grids are online, and the GRACE monthly grids using the corrected GIA are also online.
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New animations from NASA/University of Texas show seasonal changes in the Amazon Basin. The amount of water stored in the Amazon basin varies from month to month, and can be monitored from space by GRACE.
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NASA Deputy Administrator Lori Garver and German Aerospace Center (DLR) Executive Board Chairman Johann-Dietrich W??rner signed the agreement Thursday, 10 June 2010, during a bilateral meeting in Berlin.
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GSFC's Scott Luthcke is the featured Climate Scientist in a Union of Concerned Scientists story about how GRACE measures ice mass loss on Greenland.
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A team of researchers used Grace data to estimate Antarctica's ice mass between 2002 and 2009. Their results, published Nov. 22 in the journal Nature Geoscience, found that the East Antarctic ice sheet is losing mass, mostly in coastal regions, at an estimated rate of 57 gigatonnes a year.
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There are strong indications that mass loss from the Greenland ice sheet has recently accelerated after atmospheric warming and increased runoff and increased ice discharge through the acceleration of outlet glaciers in the west and east.
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The 2009 GRACE Science Team Meeting was held 5-6 November 2009 in Austin, Texas USA. For information on the meeting, see http://www.csr.utexas.edu/grace/GSTM/agenda.html
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Researchers estimate that a rise in sea level from the rapid collapse of the West Antarctic Ice Sheet would be on the order of 3.3 meters, approximately half of previous estimates. The consequences of such an event would be felt more profoundly along the Pacific and Atlantic coasts of the United States.
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Global monitoring of Earth???s fresh water can best be done from space. The Discovery Channel???s Planet Earth series includes a highlight on the value of GRACE data in the ???Freshwater??? segment.
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Study lead, NASA???s Eric Rignot, says the increased contribution of Antarctica to global sea level rise indicated by the study warrants closer monitoring.
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Mississippi basin water storage observed with GRACE, assimilated into numerical hydrologic model. This approach brings the GRACE accuracy from scales useful for water cycle and climate studies to scales needed for water resources and agricultural applications
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