Assessing evolution of ice caps in Suðurland, Iceland, in years 1986 - 2014, using multispectral satellite imagery

Sammanfattning: The study focuses on the application of multispectral satellite imageries in glaciological studies. It aims to assess how the Icelandic glaciers have evolved over the last decades (from the 1980s to 2014). The study area covers Mýrdalsjökull and Eyjafjallajökull ice caps located in Suðurland, Iceland. The cryosphere is an integral part of the global climate system. Its occurrence is dependent on climatic conditions but also significantly affects the climate. Ongoing climate change is most pronounced in the Arctic and the impacts on the cryosphere have accelerated during the last decades. Data and methods The analysis is based on Landsat data. They include both mapping the spatial extent of the glaciers as well as defining the equilibrium line altitude (ELA). Several remote sensing techniques are used in order to determine the best semi-automated approach. The best results were obtained by using the Normalized Difference Snow Index (NDSI) to determine the boundaries of glaciers, and Red / Near-Infrared ratio images to determine accumulation and ablation zones (and thus find ELA). Results and conclusions The ice caps of the Mýrdalsjökull group have dramatically reduced their surface area during the last decades. Eyjafjallajökull has decreased by more than 40%. Once joined, currently, the ice caps form two separate ice bodies. These results are consistent with the Global Land Ice Measurements from Space (GLIMS) program findings and the changes in termini positions observed by World Glacier Monitoring Service (WGMS) and Iceland Glaciological Society. The dominant driving factor for such a dramatic change seems to be an increase in temperature associated with observed global climate warming.