Svalbard Ice-Mass Evolution in past and future - Climate forcing and Teleconnections (SvIMEv-CT): 4th year

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Climate change is one of the major challenges humanity has to face during the 21st century. Its effects are numerous with increased mass loss from mountain glaciers and ice caps and their sub-stantial contribution to sea level-rise being among the most prominent. In this context, Arctic glaci-ers and ice caps are especially important due to their extensive ice volume and due to their large surface area that acts as a contact surface to climate and oceanic forcing and thus to climate change itself. The Arctic is, moreover, the region of highest predicted future air-temperature in-creases. Therefore, the importance of losses of ice masses in the Arctic and their contribution to sea-level rise is expected to even increase in the future.The aim of the project is to achieve reliable projections of the spatial and temporal variability of future climatic mass balance and ice-mass evolution of all glaciers and ice caps of Svalbard ac-cording to the four commonly considered future climate scenarios RCP 2.6, RCP 4.5, RCP 6.0 and RCP 8.5. Each of these scenarios will be represented by an ensemble of ten different global circulation models. The necessary modelling will be done using the spatially distributed climatic mass balance model developed and setup during the first three years of the SvIMEv-CT project. During the 4th year of the project, the model will be extended to a coupled "glacier-change model" that accounts for fluctuations of glacier surface topography and surface extent on annual intervals. The accuracy and reliability of this glacier-change model will be tested for the example of two specific glaciers in central Svalbard (Elfenbeinbreen and Sveigbreen). Comparison of the obtained results will be done against known glacier-retreat stages over recent years and against glacier-change projections obtained by using a 1D flow-line model. The glacier-change model will be forced by spatially distributed, statistically downscaled air temperature and precipitation data from the ten global circulation models and by modeled net shortwave radiation fluxes. The latter account for modelled, spatially distributed surface albedo variability and global circulation model-derived cloud-cover conditions. The model will be run over the entire 21st century in order to obtain projections of glacier mass balance, of glacier area and volume changes as well as of the associated sea level-rise contributions of the ice masses of Svalbard until 2100.