The Cryosphere, 6, 1175-1186, 2012
www.the-cryosphere.net/6/1175/2012/
doi:10.5194/tc-6-1175-2012
© Author(s) 2012. This work is distributed
under the Creative Commons Attribution 3.0 License.
Sensitivity of Greenland Ice Sheet surface mass balance to surface albedo parameterization: a study with a regional climate model
J. H. van Angelen1, J. T. M. Lenaerts1, S. Lhermitte2, X. Fettweis3, P. Kuipers Munneke1, M. R. van den Broeke1, E. van Meijgaard2, and C. J. P. P. Smeets1
1Institute for Marine and Atmospheric Research Utrecht, Utrecht University, The Netherlands
2Royal Netherlands Meteorological Institute, De Bilt, The Netherlands
3Department of Geography, University of Liège, Belgium

Abstract. We present a sensitivity study of the surface mass balance (SMB) of the Greenland Ice Sheet, as modeled using a regional atmospheric climate model, to various parameter settings in the albedo scheme. The snow albedo scheme uses grain size as a prognostic variable and further depends on cloud cover, solar zenith angle and black carbon concentration. For the control experiment the overestimation of absorbed shortwave radiation (+6%) at the K-transect (west Greenland) for the period 2004–2009 is considerably reduced compared to the previous density-dependent albedo scheme (+22%). To simulate realistic snow albedo values, a small concentration of black carbon is needed, which has strongest impact on melt in the accumulation area. A background ice albedo field derived from MODIS imagery improves the agreement between the modeled and observed SMB gradient along the K-transect. The effect of enhanced meltwater retention and refreezing is a decrease of the albedo due to an increase in snow grain size. As a secondary effect of refreezing the snowpack is heated, enhancing melt and further lowering the albedo. Especially in a warmer climate this process is important, since it reduces the refreezing potential of the firn layer that covers the Greenland Ice Sheet.

Citation: van Angelen, J. H., Lenaerts, J. T. M., Lhermitte, S., Fettweis, X., Kuipers Munneke, P., van den Broeke, M. R., van Meijgaard, E., and Smeets, C. J. P. P.: Sensitivity of Greenland Ice Sheet surface mass balance to surface albedo parameterization: a study with a regional climate model, The Cryosphere, 6, 1175-1186, doi:10.5194/tc-6-1175-2012, 2012.
 
Search TC
Final Revised Paper
PDF XML
Citation
Discussion Paper
Share