A team of researchers led by the French University of Grenoble-Alpes and the Scottish University of Edinburgh has created a new one very high resolution mapthe most detailed ever obtained so far, of territory buried under the ice of Antarctica. The map, obtained from satellite images and from the analysis of ice flowreveals a very complex landscape made up of mountain ranges, tens of thousands of hills, plains and valleys hundreds of kilometers long. Know the topography of the Antarctic continent is fundamental because affects the speed at which the ice flows towards the sea and therefore also the rise in sea levels due to climate change.
The world under the Antarctic ice sheet
Up to 34 million years ago, in Antarctica, the climate was temperate and the landscape was ice-free. Afterwards, a global climate coolingdue to the decrease in CO2 in the atmosphere, led to the formation of ice cap. Ice covered almost the entire continent. Obtaining a detailed map of the landscape beneath the ice cap is very complex because land and aerial surveys are extremely difficult. Despite this, thanks to data collected over 60 years of survey campaigns, it had recently been possible to create a high-resolution map as part of the Bedmap3 project. Now one has been published even more detailed mapobtained by combining high-resolution satellite images of the ice sheet surface with radar measurements of ice thickness. A method called Ice Flow Perturbation Analysis (IFPA), which uses the laws of physics to calculate how the ice moves: by analyzing how this flows, it was possible to obtain the topography (the ice flows faster above the valleys and less above the ridges, which hinder it).
In essence, the surface of the ice cap deforms in response to the conformation of the underlying territory. It thus turned out that at an average depth of more than 2 km under the ice there are ridges of mountain ranges, tens of thousands of hills, very long valleys and a 400 km long channel in the Maud subglacial basin. Many of these forms were previously unknown.
Why is it important to know the topography of the continent?
As we said, the bedrock shapes determine the speed by which the overlying ice retreats or slides towards the sea. Knowing it is essential for predict the effects of climate changeresponsible in some areas of Antarctica for particularly rapid melting which contributes significantly to sea level rise. Thanks to the information provided by the new map, it will be possible to identify the most vulnerable areas of the shell and perfect the forecasting models on the evolution of the effects of climate change, for example those relating to sea level rise. This work represents a significant step forward, but even more detailed versions of the Antarctic bedrock map will be needed to further improve the models.
