Estimation of the Greenland ice sheet surface mass balance for the 20th and 21st centuries X. Fettweis1, E. Hanna2, H. Gallée3, P. Huybrechts4, and M. Erpicum1 1Département de Géographie, Université de Liège, Liège, Belgium 2Department of Geography, University of Sheffield, Sheffield, UK 3LGGE – Laboratoire de Glaciologie et Géophysique de l'Environnement, Grenoble, France 4Departement Geografie, Vrije Universiteit Brussel, Brussel, Belgium
Abstract. Results from a regional climate simulation (1970–2006) over the
Greenland ice sheet (GrIS) reveals that more than 97% of the
interannual variability of the modelled Surface Mass Balance (SMB) can
be explained by the GrIS summer temperature anomaly and the GrIS annual
precipitation anomaly. This multiple regression is then used to
empirically estimate the GrIS SMB since 1900 from climatological time
series. The projected SMB changes in the 21st century are investigated
with the set of simulations performed with atmosphere-ocean general
circulation models (AOGCMs) of the Fourth Assessment Report of the
Intergovernmental Panel on Climate Change (IPCC AR4). These estimates
show that the high surface mass loss rates of recent years are not
unprecedented in the GrIS history of the last hundred years. The minimum
SMB rate seems to have occurred earlier in the 1930s and corresponds to a zero SMB rate.
The AOGCMs project that the SMB rate of the 1930s would be common at the end of 2100. The
temperature would be higher than in the 1930s but the increase of accumulation in the 21st
century would partly offset the acceleration of
surface melt due to the temperature increase. However, these assumptions
are based on an empirical multiple regression only validated for
recent/current climatic conditions, and the accuracy and time
homogeneity of the data sets and AOGCM results used in these estimations
constitute a large uncertainty.
Citation: Fettweis, X., Hanna, E., Gallée, H., Huybrechts, P., and Erpicum, M.: Estimation of the Greenland ice sheet surface mass balance for the 20th and 21st centuries, The Cryosphere, 2, 117-129, doi:10.5194/tc-2-117-2008, 2008.