Scientists See Record Decline In Greenland And Antarctic Ice Sheets b4in.org/p7mm Data from the European Space Agency’s (ESA) CryoSat-2 spacecraft has been used to map elevation and elevation changes in both Greenland and Antarctica by a team of researchers from the Alfred Wegener Institute (AWI) in Germany. The new maps, which are the most complete to ever be created from a single satellite mission, reveal the ice sheets are losing volume at an unprecedented yearly rate (approximately 500 cubic kilometers). The study findings and maps were recently published in The Cryosphere. “The new elevation maps are snapshots of the current state of the ice sheets. The elevations are very accurate, to just a few meters in height, and cover close to 16 million km2 (6.2 million square miles) of the area of the ice sheets. This is 500,000 square kilometers (193,000 square miles) more than any previous elevation model from altimetry”, said Dr. Veit Helm, glaciologist at AWI. The research team analyzed data retrieved from the CryoSat-2′s altimeter SIRAL. Satellite altimeters use radar or laser pulses sent towards Earth to measure the height of an ice sheet. The signals reflect off the surface of the sheet and the surrounding water to be recaptured by the satellite. Just over a year’s worth of data — including 7.5 million elevation measurements for Greenland and 6.1 million for Antarctica collected in 2012 — allowed the team to precisely determine the elevation of single glaciers and create the detailed maps. The maps illustrate more than just the present highs and lows of the ice sheets. They also reveal how the elevation has changed between 2011 and 2014. Ice sheet mass is gained through snowfall and lost through melting and accelerating glaciers that push ice from the interior of the sheet to the ocean. Understanding how ice thickness across Greenland and Antarctica has changed is vital according to the research team in order to model ice movements and understand exactly how much ice sheets contribute to rising sea levels. More b4in.org/p7mm
Posted on: Sat, 23 Aug 2014 05:56:49 +0000
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