Performance of MAR (v3.11) in simulating the drifting-snow climate and surface mass balance of Adelie Land, East Antarctica

• Main Authors: Amory, Charles, Kittel, Christoph, Toumelin, Louis, Agosta, Cécile, Delhasse, Alison, Favier, Vincent, Fettweis, Xavier
• Format: Text
• Language: English
• Published: 2020
• Subjects: Antarctic; East Antarctica; The Antarctic; Adelie Land; Antarc*; Antarctica; Ice Sheet
• Online Access: https://doi.org/10.5194/gmd-2020-368; https://gmd.copernicus.org/preprints/gmd-2020-368/

Drifting snow, or the wind-driven transport of snow particles and their concurrent sublimation, is a poorly documented process on the Antarctic ice sheet, inherently lacking in most climate models. Since drifting snow mostly results from erosion of surface particles, a comprehensive evaluation of this process in climate models requires a concurrent assessment of simulated transport and the surface mass balance (SMB). In this paper a new version of the drifting-snow scheme currently embedded in the regional climate model MAR (v3.11) is extensively described. Several important modifications relative to previous version have been implemented and include notably a parameterisation for drifting-snow compaction, differentiated snow density at deposition between precipitation and drifting snow, and a rewriting of the threshold friction velocity for snow erosion. Model results at high resolution (10 km) over Adelie Land, East Antarctica, for the period 2004–2018 are presented and evaluated against available near-surface meteorological observations at half-hourly resolution and annual SMB estimates. MAR resolves the local drifting-snow frequency and transport up the scale of the drifting-snow event and captures the resulting observed climate and SMB variability. This suggests that this model version can be used for continent-wide applications, and that the approach of drifting-snow physics as proposed in MAR can serve as a basis for implementation in earth system models.