Greenland Ice Sheet Meltwater Export and River Discharge

Abstract:

The Greenland ice sheet supplies massive amounts of freshwater and sediments to surrounding oceans, contributing to global sea level rise and influencing marine ecosystems. A large portion of this meltwater runoff flows through rivers draining the entire perimeter of the ice sheet. These unique river systems are characterized by strong seasonality, high sediment loads due to glacial erosion, and variable basin size and hypsometry over a melt season, during which the melting front propagates upwards and engages an increasingly larger drainage basin area. Other sources of Greenland streamflow include runoff from tundra areas, peripheral glaciers and ice caps. Despite the uniqueness and importance of Greenland surface streams, a comprehensive, comparative study of these systems has not been made. Here, we present an investigation of these systems and analyze their role in the total Greenland meltwater export to the ocean. River catchment areas are identified by analyzing high-resolution digital elevation models of ice sheet surface topography. Discharge from individual rivers are derived from the regional surface mass balance model Modèle Atmosphérique Régional (MAR). Our inventory of Greenland Rivers’ hydrological regime, characteristics, and emerging trends provides insights into the current and future state of Greenland streamflow.