Antarctic Ice Sheet Grounding Line Traced from Space
26.07.2010 - Atmosphere & Space, Water & Oceans, Ice & Snow, Antarctic
Establishing the grounding line of the largest freshwater reserve on Earth – the Antarctic Ice Sheet – is important in helping scientists determine exactly how much mass the ice sheet is losing to the ocean and thus how much it’s contributing to global sea level rise. Now, the Antarctic Surface Accumulation and Ice Discharge (ASAID) has provided the most accurate tracing yet of the Antarctic grounding line (where the ice sheet leaves land and moves out over the water).
To construct the map, a team of NASA and international scientists combined high-resolution images of the continent from the Landsat 7 satellite and new computer software and then connected no less than 3,574,365 points around Antarctica to trace the 53,610 km-long grounding line. Robert Bindschadler of NASA's Goddard Space Flight Center called it a major achievement of the IPY 2007-08.
After producing the new map of the Antarctic grounding line, the team will use NASA’s ICESat satellite to determine the ice thickness at the grounding line. Once all of these elements are determined, the full data set will be turned over to the National Snow and Ice Data Center (NSIDC) for further analysis.
Scientists had estimated Antarctic Ice Sheet losses by calculating the speed of outflow from 33 of Antarctic’s outlet glaciers; however these only account for half of what is lost and cover only 5% of the coast. But with a more accurate map of the Antarctic grounding line and improved data sets on ice thickness and velocity, scientists will now be able to get a much more accurate estimate of discharge from the Antarctic Ice Sheet.
