Fresh Water Fluxes

The Arctic Ocean receives freshwater by run-off from Asia north of the Himalaya. Large rivers carry freshwater from this enormous catchment area into the Eurasian shelf seas. Ocean waters with salinities below the average salinity of the Arctic Ocean also contribute positively to the fresh water balance of the Arctic Ocean. Such waters flow in from the Nordic Seas.

An interchange of waters between the Arctic and the Nordic seas results in in seasaw fluctuations in fresh water content between the basins. To reach an equilibrium, the Arctic Ocean must on averageexport freshwater. Major pathways of the export are the East Greenland Current and sea ice flux through Fram Strait. Inflow of saline water from the South is equivalent to a fresh water export. Fresh water from the Arctic strengthens the stratification in the Nordic Seas and the Labrador Sea. Strong stratification prevents downward transport that usually occurs in these ocean where the northern downward branch of the Atlantic Meridional Overturning Circulation (AMOC) is normally situated.

To better understand the interbasin exchanges of fresh water we employ ocean sea ice and large scale Earth System models. The models are validated using sea ice drift estimates from satellite remote sensing and regional airbornesea ice thickness measurements. Oceanographic moorings in Fram Strait provide estimates of liquid fresh water transport. Once validated, the models can be used for numerical experiments that reveal the forcing of fresh water transport and the relationship between fresh water storage in the Arctic Ocean and release of fresh water to the Nordic Seas in export events. The large scale consequences of such events for the oceanic circulation and regional sea level  changes are also studied in such experiments.