Univeristé de Liège &
Geological Survey of Greenland and Denmark
The University of Liège and Geological Survey of Greenland and Denmark plan to validate current modelled surface mass balance estimates by performing snow pits measurements of winter snowfall accumulation over the Greenland Ice Sheet.
Due to the global warming, surface melt is projected to significantly increase over the Greenland ice sheet but this melt acceleration will be in part mitigated by heavier snowfall in winter. However, large discrepancies remain in the climate model simulating these two components of the surface mass balance, in particular along the South-east coast where there is no measurement and where the maximum of precipitation is simulated. The 600 km traverse of Nanok will be a unique opportunity to access to this wild area by performing snow pits measurements which will help us to validate current modelled surface mass balance estimates.
At the end of each expedition day, we propose to dig (of ~ 1m) a well in the snowpack until reaching the more dense snowpack (firn) which has melted last summer in the aim of i) estimating the amount of winter accumulated fresh snow from the last summer (i.e. from September 2021 to April 2022) as well as ii) the density of this fresh snowpack. This data will allow to better quantify the spacial variability of the snowfall over the Greenland ice sheet in the ultimately aim of validating the surface mass balance models performing future projections over the Greenland ice sheet.
As shown in Fettweis et al. (2020), it remains large discrepancies in modelled precipitation along the south-west coast of Greenland but no observation is currently available to evaluate the models in this area. The Nanok expedition will be a unique opportunity to perform for the 1st time in situ measurements in this difficult of access area, in the final aim of better quantifing the mitigating role of increasing precipitation in the expected future sea level rise from the Greenland ice sheet.
Fettweis et al. 2020, GrSMBMIP: intercomparison of the modelled 1980–2012 surface mass balance over the Greenland Ice Sheet, The Cryosphere