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article imageWhat Antarctica looks like without ice — the Bedmap 2 Project

By Robert Myles     Mar 30, 2013 in Science
A new study of the physical properties of the Antarctic landmass has revealed the most detailed map yet produced, showing a landscape of mountain ranges gorges and ravines significantly deeper than ever imagined.
Scientists having been mapping the Antarctic for years but the latest study, Bedmap2, the result of collaboration between the British Antarctic Survey and a host of international agencies, has produced the most detailed information yet about the frozen continent. The new study, highlighted on Techhive, shows that a far greater proportion of the Antarctic land mass (as opposed to the ‘icing’ of glacial ice) lies below sea level than was previously thought.
Bedmap 2 is the successor to the original Bedmap which was completed in 2001. Bedmap 2 has moved Antarctic mapping to a new level and measures surface elevation, ice-thickness, the sea floor and subglacial bed elevations of the Antarctic south of latitude 60°S. Compiling new maps involved taking 25 million measurements of ice thickness in the process. Measurements of ice volume, depth, and sub-glacial landmass were taken by using a variety of sources. Radio echo sounding measurements, seismic techniques, satellite readings and cartographic data were all used during Bedmap 2.
Bedmap 2 s most up to date map of Antarctica wthout the ice
Bedmap 2's most up to date map of Antarctica wthout the ice
British Antarctic Survey
Talking about the new Antarctic maps, Dr Hamish Pritchard, co-lead author of the study, said on the British Antarctic Survey (BAS) website:
“The Bedmap2 project is about more than making a map of the landscape. The data we've put together on the height and thickness of the ice and the shape of the landscape below are fundamental to modelling the behaviour of the ice sheet in the future. This matters because in some places, ice along the edges of Antarctica is being lost rapidly to the sea, driving up sea level. Knowing how much the sea will rise is of global importance, and these maps are a step towards that goal."
As well as the new mapping process allowing scientists to ‘view’ Antarctica’s sub-glacial landscape in far greater detail than previously, the data gathered for Bedmap 2 has also been used to update statistics about Antarctic ice.
According to the Bedmap 2 data:
• By volume the Antarctic ice sheet amounts to 27 million cubic kilometres
• The volume of Antarctic ice is 4.6% greater than was previously thought
• A melt of the entire Antarctic ice sheet would cause a 58 metre rise (about 190 feet) in worldwide sea-levels. This is similar to previous estimates but Bedmap 2 has enabled a much more accurate measurement to be taken.
• The average depth of the bed beneath the grounded ice sheet is 72 metres (236 feet) lower than previously thought.
• Significantly, when it comes to considering the effects of ice melt, the area of ice sheet grounded on bed below sea level is 23% higher than scientists had previously thought.
The new data has important implications for future modelling of the evolution of the Antarctic ice sheet but it is the last statistic that is particularly important when considering the effects of Antarctic ice melt. It means there is a larger volume of the Antarctic ice sheet, lying grounded below sea level, that is more prone to rapid melt. Ice that rests just below the sea level would be vulnerable to any warming of ocean currents.
The Bedmap 2 survey also returned more accurate data on the lowest point on the Earth’s crust, if the ice were absent. The bed below the Byrd Glacier in Victoria Land is 2,870 metres (about 9,400 feet) below sea level, making it the lowest point on any of the Earth’s continental plates. The new measurements put the depth at around 400 metres (about 1300 feet) deeper than was previously thought.
Commenting on the Bedmap 2 data on the BAS website, Peter Fretwell, a member of BAS said, “The new Bedmap shows, with unprecedented detail, the bedrock beneath the ice sheets of Antarctica. Before we had a regional overview of the topography, but this new map, with its much higher resolution, shows the landscape itself; a complex landscape of mountains, hills and rolling plains, dissected by valleys troughs and deep gorges."
The full research paper setting out the Bedmap 2 findings is now available for download from The Cryosphere website.
More about Antarctic, British Antarctic Survey, Bedmap, Bedmap 2 Project, Antarctic ice
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