Glacial Meltwater in the Current System of Southern Greenland

Abstract

The Greenland Ice Sheet is losing mass at an accelerating pace, increasing its contribution to the freshwater input into the Nordic Seas and the subpolar North Atlantic. It has been proposed that this increased freshwater may impact the Atlantic Meridional Overturning Circulation by affecting the stratification of the convective regions of the North Atlantic and Nordic Seas. Observations of the transformation and pathways of meltwater from the Greenland Ice Sheet on the continental shelf and in the gyre interior, however, are lacking. Here, we report on noble gas derived observations of submarine meltwater distribution and transports in the East and West Greenland Current Systems of southern Greenland and around Cape Farewell. In southeast Greenland, submarine meltwater is concentrated in the East Greenland Coastal Current core with maximum concentrations of 0.8%, thus significantly diluted relative to fjord observations. It is found in water with density ranges from 1,024 to 1027.2 kg m−3 and salinity from 30.6 to 34, which extends as deep as 250 m and as far offshore as 60 km on the Greenland shelf. Submarine meltwater transport on the shelf averages 5.0 ± 1.6 mSv which, if representative of the mean annual transport, represents 60%–80% of the total solid ice discharge from East Greenland and suggests relatively little offshore export of meltwater east and upstream of Cape Farewell. The location of the meltwater transport maximum shifts toward the shelfbreak around Cape Farewell, positioning the meltwater for offshore flux in regions of known cross‐shelf exchange along the West Greenland coast.

Summer Hydrography Conditions at Proglacial Fjord Entrances Along East Greenland

“…Thus, glacier meltwater cannot be detected at the slope and most of the Polar Water, meteoric water, and glacier meltwater are confined to the coast. This is in line with observations by Willcox et al (2023) north of our study area and Beaird et al (2023) south of our area that could not find a clear signal of meltwater from the Greenland ice sheet on the shelf either. However, it should be emphasized that in the present study, we find signals of glacier meltwater, although small along the coast.…”

“…However, it should be emphasized that in the present study, we find signals of glacier meltwater, although small along the coast. The distribution of Atlantic Water variants and Polar Water is also in accordance with previous studies (Rudels et al, 2002) and support recent indications that there is a continuous pathway for Arctic-sourced freshwater along entire East Greenland from the Fram Strait to Cape Farewell (Beaird et al, 2023;Foukal et al, 2020;Sutherland & Pickart, 2008).…”