Investigation of pre-surge dynamics at Basin 3, Austfonna

Written by Thomas Zwinger.

Surface mass balance data from the regional climate model HIRHAM5 was used to force a transient Elmer/Ice as well as a lower order model (BISICLES) simulation of Austfonna ice cap (Svalbard) from pre-surge stage at 1995 to December 2011. Basal sliding distributions at the bounding dates were inferred from satellite data and different types of temporal changes between these limiting states (step functions, linear evolution) were tested. Beyond 2011, the authors tried to deduce the evolution of the basal friction coefficients from the two inverted states, finding that the 2012 surge is a result of basal processes that are yet not represented in the model. The picture shows the inverted surface velocities for Elmer/Ice (left) and BISICLES (right) and their difference (middle).

Gong, Y., T. Zwinger, S. Cornford, R. Gladstone, M. Schäfer, and J.C. Moore, 2016. Importance of basal boundary conditions in transient simulations: case study of a surging marine-terminating glacier on Austfonna, Svalbard, Journal of Glaciology, pp. 1–12, doi:10.1017/jog.2016.121.

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