A daily, 1 km resolution Greenland rainfall climatology (1958‐2020) from statistical downscaling of a regional atmospheric climate model

A daily, gridded 1-km rainfall climatology (1958-2020) for Greenland is presented, including the Greenland ice sheet (GrIS), the peripheral glaciers and ice caps (GIC), and ice-free tundra. It is obtained by statistically downscaling the 5.5 km output of the regional atmospheric climate model version 2 to a resolution of 1 km, using the elevation dependence of snowfall fraction. Based on this new product, the average total annual rainfall in Greenland during 1958-2020 is estimated to be 111.4 +/- 11.2 Gt/year, of which 28.6 +/- 6.1 Gt/year falls on the GrIS, 11.4 +/- 1.4 Gt/year on the GIC, and 71.4 +/- 9.0 Gt/year on the tundra. The downscaled 1 km product better resolves especially the relatively small GIC, more than doubling (+124%) their rainfall compared to the 5.5 km product. The relatively warm southern regions of Greenland have the highest rainfall amounts, with annual values locally exceeding 1,000 mm. We confirm a significant positive trend in Greenland rainfall (>40 mm/decade), notably in the northwest and mainly due to an increase in rainfall fraction (>3.5%/decade) during July and August. For the whole of Greenland, during 1991-2020 the seasonal rainfall peak has shifted from July to August, with significant increases in September, which receives more rain than June. An analysis of rainfall fraction and near-surface temperature shows that local warming rates are a good predictor of recent rainfall changes.