Researchers from Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU) have investigated all glacial areas in South America in more detail than ever before, from the tropical areas of Venezuela to the subpolar regions of Tierra del Fuego. Their two major findings are that the highest rate of mass loss is in the Patagonian icesheet, and that the glaciers in the tropics have lost considerably less mass than previously projected, although this is not the good news which it might appear at first sight. The researchers' findings have been published in the journal Nature Climate Change, as part of the SPP SeaLevelSATELLITE project.
'If you compare historical photos of glaciers with those taken more recently, you can see that where there was formerly ice, there is now very often nothing but rock. Geographers, however, are less interested in the area covered by a glacier, and more interested in its mass."
Geographers from FAU specialising in both climatology and remote sensing and spatial information, led by Prof. Dr. Matthias Braun and Dr. Tobias Sauter, also used satellite data for surveying South American glaciers, but they focused on calculating elevation levels instead of basing their results on gravimetric measurements. Two radar satellites from the German Aerospace Center (DLR) have been orbiting the Earth since 2010. The aim of the TanDEM-X-mission was to obtain a three-dimensional image of the Earth, which is not only of a consistent quality but also more accurate than anything that has gone before. Differences in elevation were recorded down to the last metre. The researchers from FAU used data collected between 2011 and 2015 and compared them with measurements from the Shuttle Radar Topography Mission of 2000. Using a complex method which involved making various corrections and calculating possible error margins, they compared the data to calculate the changes in elevation in the glacial regions of South America, thus obtaining an accurate picture of the changes in glacial mass. Their method was unusual in that they were able to use one uniform method to record all glacial areas in the region. In addition, the method even provided accurate data for individual glaciers. Comparing the measurements from both space missions allowed the researchers to gain detailed insights into the situation throughout South America. For the first time, researchers succeeded in analysing the large Patagonian ice fields separately from the surrounding, smaller glaciers.
Braun, M.H., P. Malz, C. Sommer, D. Farías-Barahona, T. Sauter, G. Casassa, A. Socuro, P. Skvarca, and T.C. Seehaus (2019), Constraining glacier elevation and mass changes in S. America, Nature Climate Change, doi: 10.1038/s41558-018-0375-7.
The press release was first published here.