Spatial distribution of accumulation in the Adélie Land - Comparison of the Antarctic GLACIOCLIM-SAMBA observation data with remote sensing techniques and high-resolution climate models

The Surface Mass Balance (SMB) of Antarctica is typically much larger within the first 200 km from the coast than further inland. This is also likely where much of the SMB change is expected due to climate warming. That is why since 2004 the GLACIOCLIM- SAMBA French observatory monitors the SMB in this region with spatial scales resolving those of climate models.
A stakes line made of 91 stakes was deployed along a 150 km transect from the coast of Adélie Land towards Dome C on the plateau. This transect is surveyed each year and 3 complete records are now available.
We first compare recent SMB measurements with older reports from the 1972-1992 period. We show that a significant fraction of the observed kilometer-scale spatial variability is stationary with time. Moreover the large spatial and inter-annual variabilities of recent measurements are consistent with the historical ones. The lateral spatial significance of the transect is then evaluated using the background remote-sensing- based model of Arthern et al. (2006).
Finally, results from 3 high-resolution climate models are presented and compared with the field reports: the global atmosphere-surface climate model LMDZ4 zoomed to reach a 35 km resolution over Antarctica, the regional atmospheric climate model MAR developed for polar regions (20 km resolution) and the ECMWF analysis (50 km resolution).
We show large differences between the 3 models, which don’t have the same ability to reproduce the meso-scale characteristics of the distribution of the observed SMB in the critical coast-to-plateau area.