(By Correne Coetzer) After studying decades of data, scientists of the British Antarctic Survey (BAS) and NASA released a virtual map of Antarctica showing the White Continent without snow and ice. The new dataset, called Bedmap2, is a new suite of gridded products describing surface elevation, ice-thickness and the seafloor and subglacial bed elevation of the Antarctic south of 60°S.
BAS researchers compiled decades worth of geophysical measurements, such as surface elevation measurements from NASA's Ice, Cloud and Land Elevation Satellite, known as ICESat, and ice thickness data collected by Operation IceBridge.
A new dataset called Bedmap2 gives a clearer picture of Antarctica from the ice surface down to the bedrock below. The previous collection of Antarctic data, known as Bedmap, was produced in 2001.
Bedmap2, like the original Bedmap, is a collection of three datasets—surface elevation, ice thickness and bedrock topography. Over the past decade there have been many Antarctic surveys, which vastly increased the amount of available data. Researchers used data from satellites, aircraft and surface-based surveys to build a data product with higher resolution, greater coverage and improved precision.
The extensive use of GPS data in more recent surveys improved the precision in resolution, coverage and precision that will lead to more accurate calculations of ice volume and potential contribution to sea level rise.
Total ice volume and sea level contribution remain similar to calculations using the original Bedmap, but Antarctica's average bedrock depth, deepest point and ice thickness estimates have all increased.
Several features of the bed have been revealed for the first time including a new deepest point. The bed under the Byrd Glacier in Victoria Land is 2,870 metres below sea level making it the lowest point on any of the Earth’s continental plates.
The volume of ice in Antarctica is 4.6% greater than previously thought.
The mean bed depth of Antarctica, at 95 metres, is 60 m lower than estimated.
The volume of ice that is grounded with a bed below sea level is 23% greater than originally thought meaning there is a larger volume of ice that is susceptible to rapid melting. The ice that rests just below sea level is vulnerable to warming from ocean currents.
The total potential contribution to global sea level rise from Antarctica is 58 metres, similar to previous estimates but a much more accurate measurement.
The new deepest point, under Byrd Glacier, is around 400 metres deeper than the previously identified deepest point.
A detailed explanation of Bedmap2 is published in the Journal of Cryosphere.
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