TC The Cryosphere TC The Cryosphere 1994-0424 Copernicus Publications Göttingen, Germany 10.5194/tc-2-1-2008 Spatial structures in the heat budget of the Antarctic atmospheric boundary layer van de Berg W. J. 1 van den Broeke M. R. 1 van Meijgaard E. 2 IMAU, University of Utrecht, Utrecht, The Netherlands KNMI, De Bilt, The Netherlands 08 01 2008 2 1 1 12 Copyright: © 2008 W. J. van de Berg et al. 2008 This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 2.5 Generic License. To view a copy of this licence, visit https://creativecommons.org/licenses/by-nc-sa/2.5/ This article is available from https://tc.copernicus.org/articles/2/1/2008/tc-2-1-2008.html The full text article is available as a PDF file from https://tc.copernicus.org/articles/2/1/2008/tc-2-1-2008.pdf

Output from the regional climate model RACMO2/ANT is used to calculate the heat budget of the Antarctic atmospheric boundary layer (ABL). The main feature of the wintertime Antarctic ABL is a persistent temperature deficit compared to the free atmosphere. The magnitude of this deficit is controlled by the heat budget. During winter, transport of heat towards the surface by turbulence and net longwave emission are the primary ABL cooling terms. These processes show horizontal spatial variability only on continental scales. Vertical and horizontal, i.e. along-slope, advection of heat are the main warming terms. Over regions with convex ice sheet topography, i.e. domes and ridges, warming by downward vertical advection is enhanced due to divergence of the ABL wind field. Horizontal advection balances excess warming caused by vertical advection, hence the temperature deficit in the ABL weakens over domes and ridges along the prevailing katabatic wind. Conversely, vertical advection is reduced in regions with concave topography, i.e. valleys, where the ABL temperature deficit enlarges along the katabatic wind. Along the coast, horizontal and vertical advection is governed by the inability of the large-scale circulation to adapt to small scale topographic features. Meso-scale topographic structures have thus a strong impact on the ABL winter temperature, besides latitude and surface elevation. During summer, this mechanism is much weaker, and the horizontal variability of ABL temperatures is smaller.

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