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The Canadian Arctic Archipelago (CAA) connects the Arctic Ocean and Baffin Bay through narrow channels and is one of the key gateways where
freshwater leaves the Arctic. It has therefore the potential to affect the deep convection in the northern North Atlantic.
Volume and freshwater transports through the CAA are assessed using the unstructured-mesh Finite Element Sea ice-Ocean Model (FESOM) in a global
setup with the CAA resolved at 5 km scale. The hindcast simulation realistically represents the Arctic sea ice conditions and fluxes through
the main gates of the Arctic Ocean and through the CAA.
The interannual variability of CAA volume transports is determined by sea surface height (SSH) gradients between the Arctic Ocean and northern
Baffin Bay. The sea level upstream of Lancaster Sound is mainly determined by that along the Beaufort Sea coast, which can be explained by changes in
the wind regimes (cyclonic versus anticyclonic) associated with release or accumulation of freshwater in the Beaufort Gyre. Sea level variations
downstream of Lancaster Sound and Nares Strait are connected to SSH variations in the eastern Baffin Bay and in the Labrador Sea, which can be
attributed to the variability of ocean-atmosphere heat fluxes. Both processes upstream and downstream of the CAA are linked with the North
Atlantic Oscillation type of atmospheric variability.
The effect of mesh resolution in the CAA area is evaluated by performing experiments with and without highly resolved archipelago (5 km vs.
24 km resolution). Increased resolution in the CAA leads to higher freshwater transports through the CAA; at the same time
transports on the eastern side of Greenland are reduced. This ‘redirection’ of Arctic freshwater affects convection in the Labrador Sea
and thus the Atlantic meridional overturning circulation.

Lecturer
Claudia Wekerle
CMCC, Bologna