Inference of Submarine Meltwater in the Boundary Current System around Greenland in 2015-2019

Melting of the Greenland Ice Sheet is one of the major causes that adds to the ice sheet mass loss and subsequently to the global sea level rise. The accelerated melting observed in recent decades is mainly caused by surface melting due to atmospheric warming and submarine melting caused by the increased inflow of warm Atlantic Water into the glacier-inhabited fjords of Greenland. This water reaches the front of marine terminating glaciers or the base of floating ice tongues inducing submarine melting. However, knowledge about submarine melt rates is limited and often inferred from indirect or remote sensing methods. Open questions exist regarding the processes that control the interaction of the oceans with marine terminating glaciers and the subsequent pathway of glacially modified water. The increasing release of this meltwater into the ocean is expected to have an impact on the deep water formation in the North Atlantic causing it to decrease. Since the deep water formation and spreading contribute to the deep limb of the Atlantic Meridional Overturning Circulation, identifying, tracking, and quantifying the oceanic submarine meltwater content and its variability is of high interest. The noble gases helium and neon provide a useful tool to identify and to quantify the fraction of glacially modified water in the oceanic water column. In this study we evaluate hydrographic, velocity and noble gas measurements from a number of cruises conducted across the boundary current system around Greenland between 2015 and 2019. With focus on the East and West Greenland Current systems, we aim at obtaining a large-scale view on the submarine meltwater distribution around Greenland and discuss the different regional regimes in two Greenlandic fjord systems and the boundary current around Greenland.