Insights into the North Hemisphere daily snowpack at high resolution from the new Crocus–ERA5 product

Abstract. This article provides an overview of the daily Crocus–ERA5 snow product covering the Northern Hemisphere from 1950 to 2022. It assesses the product's performance in terms of snow depth and cover compared to in situ observations and satellite data. Compared to its predecessor, Crocus-ERA-Interim, Crocus–ERA5 benefits from improved spatial resolution and better atmospheric data assimilation, resulting in more accurate snowpack estimates, especially during spring in Eurasia. The findings show a good match with observations, though biases remain, particularly in some Arctic regions, where the model tends to overestimate spring melt. In low-vegetation areas such as tundra, Crocus–ERA5 may introduce biases due to its limited consideration of interannual vegetation changes, leading to inaccuracies in the simulation of snowmelt. The production of this snow dataset responds to the request of the continental cryosphere community. In particular the French and Canadian government institutions CNRM (National Center for Meteorological Research) and ECCC (Environment and Climate Change Canada) have been involved in monitoring Arctic snow cover as part of the ”Terrestrial Snow” section of the Arctic Report Card since 2017. The Crocus–ERA5 product is freely available on a daily basis and at 0.25° resolution over the 1 July 1950 to 30 June 2023 period (Decharme et al., 2024, https://doi.org/10.5281/zenodo.14513248).