The residual diapycnal overturning circulation through interior regions of the Nordic Seas is diagnosed. The mean flow is estimated from Ekman dynamics and from the thermal wind relation with reference level velocities deduced from observations and from simplified theory. Eddy-induced transport is estimated from a GM-type parameterization which includes top and bottom boundary layers. The contributions from the Eulerian mean and eddy-induced transport are then compared to the annual-mean air – sea density transformation over the Nordic Seas. The calculations suggest that the mean flow overturning may explain up to 25% of the observed air – sea transformation in the Lofoten-Norwegian Sea basins. But, over all, eddy-induced overturning must dominate the transport of buoyancy and heat into these interior regions, and the eddy parameterization used here is able to explain most of the density transformation rates. The calculations generally support previous claims that small-scale mixing is of secondary importance in high-latitude regions such as this, but they also open for the existence of a deep mixing-driven overturning cell between the eastern and western parts of the Nordic Seas.
Isachsen, Pål E., and Ole A. Nøst. 2012. "The air-sea transformation and residual overturning circulation within the Nordic Seas." Journal of Marine Research 70, (1). https://elischolar.library.yale.edu/journal_of_marine_research/332