On the Variability of Arctic-Subarctic Heat and Freshwater Exchanges from Ocean Reanalyses

Arctic-Subarctic ocean fluxes play a key role in controlling the processes, interactions, and feedbacks that subsequently drive multi-scale variability of the Arctic. Freshwater storage in the Beaufort Gyre is profoundly controlled by the atmospheric circulation regimes which in turn influence Arctic-Subarctic exchanges. Heat and freshwater fluxes through Fram and Davis Straits control the deep water mixing and water mass formation in the subarctic basins. Long-term variability and changes of heat and freshwater exports are investigated using the following ocean reanalyses: ECMWF Ocean Reanalysis System 4 (ORAS4), ECMWF Ocean Reanalysis Pilot 5 (ORAP5), GFDL Ensemble Coupled Data Assimilation 3 (ECDA3), and Simple Ocean Data Assimilation (SODA). Time series of monthly mean fluxes of heat and freshwater are calculated and statistically processed to capture some significant oceanographic features with possible relationships with North Atlantic Oscillation (NAO), Arctic Oscillation (AO) and Arctic Ocean Oscillation (AOO) Indices.