Investigations of the Greenland Ice Sheet freshwater discharges

A field expedition on board ‘Joturn Arctic’ into Sermilik Fjord on the southeast coast of Greenland was successfully completed on August 15th. Several outlet glaciers discharges freshwater into the fjord system, including one of the most rapid moving glaciers at Greenland - the Helheim glacier.

During 15 days of field observations 161 oceanographic stations with CTD profiles from the surface up to 560 meters depth (the wire length) were collected and accompanied by continuous measurements of the surface temperature and salinity, meteorological measurements and water sampling for oxygen isotopes. Totally 13 sections inside the fjord and the offshore region, where water from the fjord is mixing with the East Greenland Costal Current, were completed. These types of observations are unique and before our last year expedition no such oceanographic measurements have been made in the Sermilik fjord system. The severe ice conditions prevented the sailboat reaching the innermost parts of the fjord, which was blocked by icebergs (see picture).

Preliminary analysis of our data shows that the Sermilik Fjord is a very deep fjord with bottom depth more than 800 m (maximum depth of echo-sounding mounted on sailboat) and that the subsurface water layers have temperatures up to 4°C are of Atlantic water origin and advected from the Greenland shelf water. Further analysis of our data will improve knowledge about the stratification of the water masses in the fjord, transformation along stream and mixing processes with the Greenland shelf waters, as well as the influence of the warm deeper water on the melting of the glaciers. Comparison with 2008 data, for the first time, gives a possibility to assess an interannual variability of water mass distribution in the Sermilik Fjord area.

The investigations have been supported by the Nansen Scientific Society.