Datensatz

Zusammenfassung

Meltwater from the Greenland Ice Sheet has the potential to freshen the surface of the Labrador Sea and limit deep convection. Typically, meltwater is added to ocean models at the surface, neglecting the observed mixing of meltwater within fjords. We investigate how a more realistic representation of meltwater amplifies the transport of freshwater across the southwest Greenland shelf break. Results from four coupled ocean/sea-ice simulations forced with atmospheric reanalysis are compared for the years 1992-1993. We compare eddy permitting and mesoscale eddy resolving (horizontal resolutions of approx. 5km and 3km in the study region, respectively) simulations with no meltwater to examine the importance of mesoscale processes in off shelf transport. Two different meltwater forcing schemes are implemented in the mesoscale eddy resolving configuration: meltwater added to the surface layer and meltwater vertically distributed over the upper 200m. When meltwater is added, there is an increase in off shelf freshwater transport (S<u>ref</u>=34.7) compared to the no-meltwater case (total transport of 45.2 ~mSv). Transport off the shelf increases by 12mSv in the surface meltwater case and by 23.1mSv in the vertically distributed meltwater case. In the mesoscale eddy resolving simulations, when meltwater is vertically distributed, there is enhanced baroclinic conversion at the shelf break compared to the simulation with no meltwater. This suggests that meltwater from the Greenland Ice Sheet could have a disproportionate impact on freshwater transport into the Labrador Sea by modifying cross shelf exchange.