Modelling of the dynamics of Fimbulisen, Antarctica

This project aims to understand the dynamics of Fimbulisen, situated in Haakon VII Sea, Antarctica. Antarctic ice shelves drain 90% of the coastward mass flux of the inland ice sheet. Ice shelves are sensitive elements of the climate system, since they are in contact with ocean and atmosphere, which are both affected by climate warming. In the past 7 ice shelves along the Antarctic Peninsula have completely disintegrated. With the spectacular break-up of Larsen-B Ice Shelf the question of ice shelf stability has once more come to the fore.

Fimbulisen is located at the coast of Dronning Maud Land and is the only ice shelf that is overhanging the continental shelf. This exposed position allows warm ocean water draining into the ice shelf cavity and produces high melt rates. The high melt rates likely cause the unusual temperature-depth profile of the ice, decreasing up to 10°C towards the bottom, that is measured exclusively at this ice shelf. The temperature profile of the ice has a direct influence on the velocity of the flow, because Glen's flow law exhibits a the strongly temperature-dependent flow-rate factor. The shape of the temperature profile itself is driven by surface and bottom accumulation rates.

That requires knowledge of the melt rates beneath the ice shelf, and thus of the ocean dynamics. Therefore, the best procedure is a coupling between an ice shelf model and an ocean model. The elliptic boundary-value problem for the horizontal velocity in the shallow-shelf approximation and the temperature and ice thickness evolutions will be solved by means of numerical solutions by finite element technique. Simulation of other ice shelves showed that the incorporation of local features, e.g. shear margins and rifts, improve the quality of diagnostic simulations. Those features are detected in satellite images and transfered into the numerical code. The effects of climate change will be investigated with sensitivity tests by increased ocean and ice surface temperatures. Local ice surface temperature trends will be derived from brightness temperatures, in order to reflect the real ice surface temperatures on Fimbulisen.

Scientists

Dr. Angelika Humbert
Institute of Geophysics
University of Muenster

Research areas

Fimbulisen 69.5-71.5°S, 3°W-8°E

Publications

Humbert A, 2006. Numerical simulations of the ice flow dynamics of Fimbulisen. In: L. H. Smedsrud (ed.), Forum for Research into Ice Shelf Processes (FRISP) Report No.17 , pp. 67-78. Bjerknes Centre for Climate Research, Bergen, Norway. URL: http://www.uib.no/people/ngfls/frisp/FRISPRep17.html.

Humbert A, 2010. The temperature regime of the Fimbul Ice Shelf. Ann. Glac. 55 (accepted)

Homepage

Dr. Angelika Humbert
Dynamics of Fimbulisen

Research funding organisation

German Research Foundation

Project number: HU 1570/2-1
Funding period: Januar 2008 - December 2009