Modelling impacts of opening/closure of Arctic gateways during interglacial stages

English Abstract:

The Canadian Arctic Archipelago (CAA) and the Bering Strait are two of the key gateways that connect the Arctic Ocean to the Atlantic and Pacific Oceans, respectively. Changes in the sea ice-freshwater flux through these gateways have the potential to significantly affect the sea-ice distribution in the Arctic and the salinity in North Atlantic subarctic basins. The relative size of the freshwater fluxes into the Atlantic through the CAA influences the location and intensity of dense water formation which might have important consequences on the strength of the Atlantic meridional overturning circulation. We investigate the impact of opening/closure of the Arctic gateways (due to Tectonic movements or changes in the sea-level) on the sea-ice distribution and water pathways of the Arctic and subarctic North Atlantic during interglacials. We specifically focus on the Baffin Bay and Labrador Sea. An eddy-permitting regional configuration of the NEMO coupled ocean/sea-ice model is used. The regional domain covers the Arctic Ocean and the Northern-Hemisphere Atlantic, with a horizontal resolution of 1/4 degree at the equator (ANHA4). We set-up several sensitivity experiments by closing either one or both of the CAA and Bering gateways to know the individual impacts of each gateway. Boundary conditions are obtained from the global climate models for Holocene and MIS-5. The model results are compared with the paleoclimate data from Arctic and subarctic seas to further understand the climate conditions during interglacial stages.