Snow Mass Recharge of the Greenland Ice Sheet Fueled by Intense Atmospheric River

Abstract

Atmospheric rivers (ARs) have been linked with extreme rainfall and melt events across the Greenland ice sheet (GrIS), accelerating its mass loss. However, the impact of AR-fueled snowfall has received less attention, partly due to limited empirical evidence. Here, we relate new firn core stratigraphy and isotopic analyses with glacio-meteorological data sets from SE Greenland to examine an intense AR in mid-March 2022. We demonstrate that the associated snowfall—up to 11.6 gigatons d⁻¹—delayed summer melt onset by11-days and offset Greenland's 2022 net mass loss by 8%. Since 2010, our synoptic analysis reveals that snow accumulation across SE Greenland increased by 20 mm water equivalent a⁻¹, driven by enhanced Atlantic cyclonicity. We find that the impact of ARs on the GrIS is not exclusively negative and their capacity to contribute mass recharge may become increasingly significant under ongoing Arctic amplification and predicted poleward intrusion of mid-latitude moisture.