[A-CG42] Science in the Arctic Region

[ACG42-P18] Modeling meltwater pathways from Greenland Ice Sheet and coastal dynamics around Greenland

*Kazuya Kusahara¹, Yoshiki Komuro¹, Fuyuki SAITO¹, Hiroaki Tatebe¹ (1.Japan Agency for Marine-Earth Science and Technology)

Much attention has been paid to the recent increase in freshwater supply from the Greenland Ice Sheet (GrIS). In this study, we conduct numerical experiments of a global sea ice-ocean model with a 0.25° resolution in a realistic configuration to investigate the pathways of GrIS meltwater and its impacts on the surrounding sea-ice and ocean fields. First, we examine the detailed pathways of the meltwater originating from the GrIS in 30-year-long passive tracer experiments. The model demonstrates that the GrIS meltwater is concentrated in coastal currents circulating around Greenland and effectively spreads over Baffin Bay. Furthermore, it is found that the meltwater is efficiently transported southward by the Labrador Current and then by the North Atlantic Current to the eastern North Atlantic and eventually to the Barents Sea. Next, a comparison of numerical experiments with and without the GrIS meltwater revealed that the GrIS meltwater contributes to regional ocean stratification and the delay of sea ice melting in the surrounding oceans. The GrIS meltwater increases the velocity of coastal currents circulating around Greenland by up to 10%. To further understand the ocean circulation around Greenland, we introduce for the first time a regional overturning circulation function based on semi-closed regions defined by the distance from the GrIS coastline. The newly-defined function illustrates that there is a wind-driven downwelling of about 1.5 Sv around Greenland, and the seasonal and interannual variability is well explained by Arrested Topographic Waves driven by wind stress along the Greenland coast.