The British Antarctic Survey (BAS) has compiled a detailed topographical map using a wide range of datasets to reveal what lies beneath Antarctica's ice sheet.

Bedmap2 builds on a previous iteration called Bedmap, which was built more than ten years ago. The map incorporates decades of geophysical data from satellites, aircraft and surface-based surveys to create a much higher resolution version.

Bedmap2's image of Antarctica's icy surface NASA's Goddard Space Flight Center


BedMap2 allows researchers to see many more surface and sub-ice features that were too small to be covered by the previous iteration of the map

There have been many Antarctic surveys over the last ten years, which have given researchers a large amount of data to play with.

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The three core datasets were surface elevation (taken from Nasa's Ice, Cloud and Land Elevation Satellite (ICESat), ice thickness data collected from an airborne radar mission called Operation IceBridge and bedrock topography data. The latter is measured by beaming radar signals down through the ice and recording the angel and timing of returning waves in order to image the ice surface, internal layering and the rocky under-layer.

BedMap2 allows researchers to see many more surface and sub-ice features that were too small to be covered by the previous iteration of the map. The map also covers more ground and in more precision -- thanks to advancements in GPS -- which means that researchers will be able to make more accurate calculations about ice volume and potential contribution to sea level rise as climate change takes effect.


The lower-resolution map created by the first iteration of Bedmap NASA's Goddard Space Flight Center

While estimates for total ice volume and sea level contribution have remained similar to those calculated ten years ago, the researchers have increased estimates for the average bedrock depth, deepest point and ice thickness.

Peter Fretwell, a scientist at BAS and lead author of the study, said that the new dataset would be an important resource for "the next generation of ice sheet modellers, physical oceanographers and structural geologists".


Ice sheet researchers use computer models to simulate how the thick, dome-shaped formations of ice respond to changes in sea and air temperatures. The two main ice sheets on Earth cover Greenland and Antarctica. They are formed by many years of snow that gets compacted into ice and they tend to grow and spread outwards "like honey poured on a plate", in the words of Nasa ice sheet scientist Sophie Nowicki. The simulations are only as good as the data relating to ice volume and the shape of the structure of the sub-ice rock, since these affect how the ice will move.

Nasa supplied much of the data for BedMap2 for free, despite the fact that collecting it was very expensive. Fretwell said of Nasa's generosity: "We hope that other partners will also go down this road."