Satellite finds variations where ice is melting fastest in Antarctica
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An Esa satellite has found an unusual consequence of the melting of ice in Antarctica.
While rising sea levels and changing global temperatures are already known to be a consequence of alleged manmade climate change, the GOCE satellite - which was not intended to study the effects of a warming climate - has found that gravity is weakening where ice is melting the fastest.
The results show that the thinning ice sheet from November 2009 to June 2012 caused local variations in gravity, measured by the satellite.
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Researchers from Nasa's Jet Propulsion Laboratory in California and elsewhere have found that gravity is weakening at Earth's poles. In this graphic a combination of data from Esa's GOCE mission and Nasa's Grace satellites shows the 'vertical gravity gradient change'. Blue is the biggest change, red the least
The GOCE satellite burned up in Earth's atmosphere as planned in November 2013 after four years in orbit.
During its mission it measured Earth's gravity in unprecedented detail, detailing where it was weakest and strongest on the surface.
But recently, the high-resolution measurements from GOCE over Antarctica between November 2009 and June 2012 were analysed by scientists from the German Geodetic Research Institute, Delft University of Technology in the Netherlands, the Jet Propulsion Laboratory in California and the Technical University of Munich in Germany.
Scientists found that the decrease in the mass of ice during this period was mirrored in GOCE's measurements of gravity, even though the mission was not designed to detect changes over time.
The findings were made by combining GOCE's high-resolution measurements with information from the Nasa-German Grace satellite, designed to measure change in ice mass.
The fluctuations observed are minute, however, and not enough for a living organism to sense.
The measurements from GOCE correlate with the Grace satellite and show how much ice is being lost each year.
While exact figures of the shift in gravity are miniscule, the results show how some parts of the West Antarctic ice sheet are losing up to 67 gigatones of ice per year.
This is contributing to a 0.51 mm per year sea level rise in the Amundsen Sea Sector.
And they found that that the loss of ice from West Antarctica between 2009 and 2012 caused the dip in the gravity field over the region.
In addition, GOCE data could be used to help validate satellite altimetry measurements for an even clearer understanding of ice-sheet and sea-level change in the future.
The changes in gravity intensity were found to be occurring where ice is melting fastest in West Antarctica due to manmade global warming. The discovery was made by the GOCE satellite, which was not originally intended to study climate change
The high-resolution measurements from the satellite are further evidence of how manmade climate change will affect the planet in unknown ways. The Goce satellite (illustration shown) burned up in Earth's atmosphere as planned in November 2013 after four years in orbit
Esa's CryoSat satellite, which carries a radar altimeter, has recently shown that since 2009 the rate at which ice is been lost from the West Antarctic Ice Sheet every year has increased by a factor of three.
And, between 2011 and 2014, Antarctica as a whole has been shrinking in volume by 30 cubic miles (125 cubic kilometres) a year.
'We are now working in an interdisciplinary team to extend the analysis of GOCE's data to all of Antarctica,' said Dr Johannes Bouman from the German Geodetic Research Institute.
'This will help us gain further comparison with results from CryoSat for an even more reliable picture of actual changes in ice mass.'
During its mission, GOCE produced a unique model of the geoid, which is essentially a virtual surface of Earth where water does not flow from one point to another. The colours in the image represent deviations in height from an ideal geoid. The blue shades represent low values and the reds/yellows represent high values
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