Interannual variability of thermal forcing in the eastern Amundsen Sea controlled by wind
Ole Rieke
Author information:
Ole Rieke1,2, Paul Spence1,2,4, Beatriz Peña-Molino2,3, Maxim Nikurashin1,2,4, Laura Herraiz-Borreguero2,3, and Matthis Auger1,4
1Institute for Marine and Antarctic Studies, University of Tasmania, Hobart, Australia
2 Australian Antarctic Program Partnership
3 Commonwealth Scientific and Industrial Research Organization Oceans and Atmosphere and Centre for Southern Hemisphere Oceans Research, Hobart, Australia
4 Australian Centre for Excellence in Antarctic Sciences
Abstract body:
- Mass loss of the Antarctic ice sheet is largest in the Amundsen Sea, West Antarctica where unrestricted access of relatively warm Circumpolar Deep Water to the continental shelf and the ice shelf cavities drives large melt rates at depth. Variability in the thermal forcing of these melt rates are insufficiently understood, leading to large uncertainty in future projections of melt rates.
- We connect sub-surface temperature from a historical simulation of the global ocean – sea ice model ACCESS-OM2-01 to observed temperature and satellite-inferred basal melt rate variability. We analyse perturbation experiments with repeat-year forcing of ACCESS-OM2-01 to investigate the mechanisms.
- ACCESS-OM2-01 is able to reproduce observed temperature variability, indicating a major role of atmospheric forcing in this variability, and a smaller role of meltwater feedbacks and internal ocean variability. Simulated temperature is controlled by changes in the southeasterly winds by a combination of immediate thermocline heaving, horizontal advection and vertical mixing.
- Physical oceanographers and glaciologists using both, models and observations
- Basal melting, Antarctic continental shelf, climate variability, ACCESS-OM2
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