Mass exchange of Atlantic Water with the Lofoten Basin derived from high-resolution Lagrangian simulations

The Atlantic Water in the Nordic Seas undergoes a substantial cooling and densification as it flows northwards towards the Arctic. The largest water mass transformation is observed to take place in the topographical depression west of the continental slope of Norway, the Lofoten Basin, due to a retention of relatively warm Atlantic Water which results in large surface heat losses. The features dominating the Atlantic Water inflow to the basin have been attributed to mesoscale eddies that drift westwards after being shed off the eastern continental slope. However, the extent of this eddy drift has not yet been quantified. Furthermore, the vertical structure and the seasonal variations of the inflow to the basin in general is not fully understood. To address these issues we perform a largest-to date deployment of 2D and 3D Lagrangian particles in the region integrated using output from a dedicated high-resolution ROMS model simulation. We estimate key inflow regions, identify the typical characteristics of these water masses and study how these characteristics change geographically around the basin. We find that while the surface inflow mainly enters the basin from the south, the inflow at deeper levels comes from the eastern continental slope. Therefore, a wavelet ridge routine on drifter trajectories is performed to identify the role of eddies on the exchanges with the basin.