Seasonal to interannual variability of temperature and salinity in the Nordic Seas: heat and freshwater budgets

Katrin Latarius1*

* Presenting author

1) University of Hamburg, Institut für Meereskunde Hamburg (IFM), Germany

Eleven years of autonomous profiling float data from the Nordic Seas are used to detect changes in temperature and salinity of the water column on time scales from seasonal to decadal. The measurements concentrate on the deep Norwegian Basin, Lofoten Basin and Greenland Sea Basin and the somewhat shallower Icelandic Plateau. Time series of temperature and salinity are dominated by the seasonal cycle in the upper 500 to 750 m. But also the longer-term development is detected. The heat and freshwater budgets reveal a similar structure for all basins: The effect of ocean-atmosphere and internal ocean fluxes on heat and freshwater is largely confined to the upper 500 m. They import heat laterally from the boundary currents below 50 m and export heat to the atmosphere and to a minor degree laterally in the upper 50 m. Freshwater is imported into the basins laterally in the upper 50 m and to a minor degree from the atmosphere. Below 50 m freshwater is exported laterally. Thus the water mass conversion from inflowing Atlantic waters to dense overflow waters in the basins is underestimated by taking only atmospheric fluxes into account. The net contribution of the basins to the water mass conversion in the Arctic Mediterranean on the whole is about 15 % although they account for only 4 % of the total area. The contribution from the eastern basins is of greater importance than the one from the western basins.

Invited talk