A Downscaling Approach Toward High-Resolution Surface Mass Balance Over Antarctica
- 164 Downloads
The Antarctic ice sheet surface mass balance shows high spatial variability over the coastal area. As state-of-the-art climate models usually require coarse resolutions to keep computational costs to a moderate level, they miss some local features that can be captured by field measurements. The downscaling approach adopted here consists of using a cascade of atmospheric models from large scale to meso-γ scale. A regional climate model (Modèle Atmosphérique Régional) forced by meteorological reanalyses provides a diagnostic physically-based rain- and snowfall downscaling model with meteorological fields at the regional scale. Although the parameterizations invoked by the downscaling model are fairly simple, the knowledge of small-scale topography significantly improves the representation of spatial variability of precipitation and therefore that of the surface mass balance. Model evaluation is carried out with the help of shallow firn cores and snow height measurements provided by automatic weather stations. Although downscaling of blowing snow still needs to be implemented in the model, the net accumulation gradient across Law Dome summit is shown to be induced mostly by orographic effects on precipitation.
KeywordsNet accumulation Downscaling Antarctica Law Dome
We acknowledge the ice2sea project, funded by the European Commission’s 7th Framework Programme through grant number 226375, ice2sea manuscript number 30. The MAR simulations were run on CNRS/IDRIS computers.
- Brasseur O, Gallée H, Creutin J-D, Lebel T, Marbaix P (2002) High resolution simulations of precipitation over the Alps with the perspective of coupling to hydrological models. Adv Global Change Res 10:75–100. M. Beniston, EdGoogle Scholar
- Collier CG (1975) A representation of the effects of topography on surface rainfall within moving baroclinic disturbances. Quart J R Met Soc 101:407–422Google Scholar
- Frezzotti M, Pourchet M, Flora O, Gandolfi S, Gay M, Urbini S, Vincent C, Becagli S, Gragnani R, Proposito M, Severi M, Traversi R, Udisti R, Fily M (2004) New estimations of precipitation and surface sublimation in East Antarctica from snow accumulation measurements. Clim Dyn 23:803–813CrossRefGoogle Scholar
- Liu H, Jezek K, Li B, Zhao Z (2001) Radarsat Antarctic Mapping Project digital elevation model version 2. National Snow and Ice Data Center. Digital media, Boulder, COGoogle Scholar
- Meehl GA, Stocker TF, Collins WD, Friedlingstein P, Gaye AT, Gregory JM, Kitoh A, Knutti R, Murphy JM, Noda A, Raper SCB, Watterson IG, Weaver AJ, Zhao Z-C (2007) Global climate projections. In: Solomon S, Qin D, Manning M, Chen Z, Marquis M, Averyt KB, Tignor M, Miller HL (eds) Climate change 2007: the physical science basis. Contribution of working group I to the fourth assessment report of the intergovernmental panel on climate change. Cambridge University Press, CambridgeGoogle Scholar
- Monaghan AJ, Bromwich DH, Fogt RL, Wang S-H, Mayewski PA, Dixon DA, Ekaykin A, Frezzotti M, Goodwin I, Isaksson E, Kaspari SD, Morgan VI, Oerter H, Van Ommen TD, Van der Veen CJ, Wen J (2006) Insignificant change in Antarctic snowfall since the international geophysical year. Science 313(5788):827–831. doi: 10.1126/science.1128243 CrossRefGoogle Scholar
- Smith RB (2002) Stratified airflow over topography. Environmental stratified flows. In: Grimshaw R (ed) Topics in environmental fluid mechanics, vol 3. Kluwer, The Netherlands, pp 119–159Google Scholar
- van de Berg WJ, van den Broeke MR, Reijmer CH, van Meijgaard E (2006) Reassessment of the Antarctic surface mass balance using calibrated output of a regional atmospheric climate model. J Geophys Res 111:D11104. doi: 10.1029/2005JD006495
- van den Broeke M (2005) Strong surface melting preceded collapse of Antarctic Peninsula ice shelf. Geophys Res Lett 32:L12815. doi: 10.1029/2005GL023247