Added Value Of The Regional Climate Model Mar Compared To Reanalyses For Estimating The Antarctic Surface Climate, 1979-2017

• Main Author: Agosta, Cécile
• Format: Report
• Language: unknown
• Published: Zenodo 2018
• Subjects: Antarctic Surface Climate; Regional Climate Modelling; Reanalyses; Antarctic; The Antarctic; Antarc*; Ice Sheet
• Online Access: https://dx.doi.org/10.5281/zenodo.1256079; https://zenodo.org/record/1256079

The Antarctic surface climate depends both on large scale circulation patterns and of local polar-specific processes. Here we show that spatial patterns of temperature and precipitation fields of 6 reanalyses products diverge significantly between each-other whereas we obtain mostly insignificant differences after downscaling with the regional climate model MAR. Downscaled surface temperature and precipitation are markedly closer to observations than the original reanalyses fields. Resolution is suspected to be a secondary parameter when compared to physical processes, as reanalyses spatial biases are comparable to higher resolution modelling with MAR whereas they are in fact of lower resolution. The temporal variability of downscaled fields is however strongly related to the forcing reanalysis variability. This study emphasis the importance of polar-specific processes and of their implementation in climate model, particularly in view of atmosphere-ice sheet coupling.