Rainfall on the Greenland Ice Sheet: Present-Day Climatology From a High-Resolution Non-Hydrostatic Polar Regional Climate Model

Greenland ice sheet rainfall is expected to increase under a warming climate. Yet, there have been no active long-term in-situ rainfall records on the ice sheet due to observational difficulties. Here, we utilize the state-of-the-art 5 km polar non-hydrostatic regional climate model NHM-SMAP to evaluate the ice sheet's rainfall over 40 years (1980-2019). The largest trends include a fourfold increase in annual rainfall for the northwestern ice sheet; 3.1 Gt year(-1) or 12 mm m(-2) year(-1). September ice-sheet-wide rainfall amount and intensity increase by 7.5 Gt month(-1) and 20.8 mm h(-1) year(-1). In the last two decades, the increasing September maximum hourly rainfall rate exceeded 50 mm h(-1) six times. The increased surface water delivery has numerous implications, including for snow metamorphism and ice flow dynamics.

Automated summary

Research shows that rainfall on the Greenland ice sheet is expected to increase as the climate warms, with the northwest part of the ice sheet experiencing a fourfold increase in annual rainfall over the past 40 years. In September, both the amount and intensity of ice sheet-wide rainfall have also significantly increased.