A high-resolution view on mesoscale eddy activity in the Eurasian Basin

Abstract

Mesoscale eddies might play a substantial role for the dynamics of the Arctic Ocean, making them crucial for understanding future Arctic changes and the ongoing ‘atlantification’ of the Arctic Ocean. However, simulating high latitude mesoscale eddies in ocean circulation models presents a great challenge due to their small size and adequately resolving mesoscale processes in the Arctic requires very high resolution, making simulations computationally expensive.Here, we use a seven-year simulation from the unstructured‐mesh Finite volumE Sea ice-Ocean Model (FESOM2) with 1-km horizontal resolution in the Arctic Ocean. This very high-resolution model setup can be considered eddy resolving and has previously been used to investigate the distribution of eddy kinetic energy (EKE) in the Arctic. Now, with a simulation spanning several years, we evaluate the changes of EKE in the Eurasian Basin and the connection to other properties like sea-ice cover, baroclinic conversion rate and stratification. EKE seasonality is influenced predominantly by sea-ice changes, while monthly anomalies have different drivers for different depths levels. The mixed layer is strongly linked to the surface and thus to sea-ice variability. Deeper levels on the other hand are shielded from the surface by stratification and influenced more strongly by baroclinic conversion.