J. Phys. IV France 121 (2004) 115-124
On the role of Antarctica as heat sink for the global atmosphereM.R. van den Broeke
Utrecht University, Institute for Marine and Atmospheric Research, PO Box 80 005, 3508 TA Utrecht, The Netherlands
We discuss the heat balance of Antarctica using observations from satellites and automatic weather stations and modelling results. Qualitatively, the surface radiation budgets of Antarctica and Greenland resemble those of large deserts, with a small net surface radiation compared to the zonal mean. As a result, atmospheric radiative cooling over the large ice sheets is significantly smaller than, for instance, over the Arctic basin. A unique feature of the large ice sheets is that the annual mean net radiation at their surface is negative. This is compensated by a flux of sensible heat from the atmosphere. This introduces additional cooling in the lower atmosphere, especially in the katabatic wind zone, where a positive feedback exists between surface cooling and downward sensible heat transport. This close interaction between the radiation climate and boundary layer dynamics makes the large ice sheets extraordinary components of the global climate system.
© EDP Sciences 2004