| Summary: | The stability of the Greenland Ice Sheet (GIS) is of critical interest to scientists and society at large in the context of future sea-level rise. The magnitude of GIS volumetric shrinkage in the coming decades depends on its glacial discharge and surface mass balance (SMB), with the later representing the balance between accumulation and surface melt. Estimates of Greenland SMB increasingly utilize climate reanalyses and high-resolution regional climate models (RCMs) to determine snow accumulation, surface melt and runoff/refreeze. These models show significant and model-dependent biases along the high-gradient edges of the GIS where the highest and most variable (in space and time) rates of accumulation and surface melt are observed. Thus, the edges of the GIS are in critical need of updated validation with in-situ accumulation and melt data, as model biases lead to significant deviations in mass balance estimates. Here we propose a traverse in the Western Greenland percolation zone over two field seasons to develop continuous in-situ snow accumulation and firn density records using ground-based radar and shallow firn cores. Our research objectives include: (1) determining the spatiotemporal patterns of snow accumulation in Western Greenland over the past 20-40 years; (2) evaluating surface melt refreeze and englacial meltwater storage in the Western Greenland percolation zone over the past 20-40 years; and (3) quantifying the accumulation and surface melt biases of the most recent climate reanalysis models and their RCM counterparts.
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