Environmental Sciences Seminar:
How Water Vapor Turns Ice into Liquid: Atmospheric River Impacts on Greenland Ice Sheet Surface Mass Balance
Among the most pressing consequences of recent climate warming is the acceleration of mass loss from the Greenland Ice Sheet (GrIS) since the late 1990s. Several episodes of widespread GrIS surface melt in recent years have coincided with intense poleward water vapor transport in narrow plumes called .atmospheric rivers. (ARs), suggesting that these events play an important role in the evolution of the GrIS. In this work, strong summer ARs are found to cause intense ice sheet melt events through complex local- to hemispheric-scale interactions between the ocean, atmosphere, and cryosphere. ARs produce ice sheet surface melt in cloudy, windy conditions in the area of AR .landfall. and in clear-sky downsloping flow in areas separated from the AR landfall by the topographic barrier of the ice sheet. Moisture fluxes during ARs originate from lower-latitude evaporative sources compared to typical conditions, with enhanced moisture uptake occurring over a broad swath of the Atlantic Ocean during summer and winter, as well as northeastern North America during summer.