Simulating the climatic mass balance of Svalbard glaciers from 2003 to 2013 with a high-resolution coupled atmosphere-glacier model

• Main Authors: Aas, Kjetil Schanke, Dunse, Thorben, Collier, E., Schuler, Thomas, Berntsen, Terje Koren, Kohler, Jack, Luks, B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus GmbH 2015
• Subjects: Austfonna; Hansbreen; Svalbard; glacier; Ice cap; The Cryosphere; The Cryosphere Discussions
• Online Access: http://hdl.handle.net/10852/56821; http://urn.nb.no/URN:NBN:no-59618; https://doi.org/10.5194/tcd-9-5775-2015

In this study we simulate the climatic mass bal- ance of Svalbard glaciers with a coupled atmosphere–glacier model with 3 km grid spacing, from September 2003 to September 2013. We find a mean specific net mass bal- ance of − 257 mm w.e. yr − 1 , corresponding to a mean annual mass loss of about 8.7 Gt, with large interannual variabil- ity. Our results are compared with a comprehensive set of mass balance, meteorological, and satellite measurements. Model temperature biases of 0.19 and − 1.9 ◦ C are found at two glacier automatic weather station sites. Simulated cli- matic mass balance is mostly within about 100 mm w.e. yr − 1 of stake measurements, and simulated winter accumulation at the Austfonna ice cap shows mean absolute errors of 47 and 67 mm w.e. yr − 1 when compared to radar-derived values for the selected years 2004 and 2006. Comparison of mod- eled surface height changes from 2003 to 2008, and satel- lite altimetry reveals good agreement in both mean values and regional differences. The largest deviations from obser- vations are found for winter accumulation at Hansbreen (up to around 1000 mm w.e. yr − 1 ), a site where sub-grid topog- raphy and wind redistribution of snow are important factors. Comparison with simulations using 9 km grid spacing reveal considerable differences on regional and local scales. In addi- tion, 3 km grid spacing allows for a much more detailed com- parison with observations than what is possible with 9 km grid spacing. Further decreasing the grid spacing to 1 km appears to be less significant, although in general precipita- tion amounts increase with resolution. Altogether, the model compares well with observations and offers possibilities for studying glacier climatic mass balance on Svalbard both his- torically as well as based on climate projections.