Eddy overturning across a shelf edge front: Kongsfjorden, west Spitsbergen

Abstract

Eddy overturning across a shelf edge front has been investigated in a simplified model setup comprising an along‐slope uniform shelf and slope with a slope current. Results from three model runs are presented, each initiated with and nudged toward a sharp shelf edge front in temperature, salinity, density, and velocity. Data collected off Kongsfjorden at Spitsbergen were used for initiating the model runs. Three distinctly different density fronts were used to initialize the model runs, one with a negative cross‐frontal density gradient toward the shelf, one with a positive density gradient, and one with a combination of negative density gradient in the upper water column and a positive in the lower water column. The model results indicate that the initial cross‐frontal density gradients determine the eddy overturning direction, acting toward flattened or terrain‐following isopycnals. The steady state modeled fronts resemble quite well the observed front structures, as well as temperature and salinity fields. This indicates that eddy overturning plays an important role in cross‐frontal exchange of water masses along the shelf edge front off west Spitsbergen. The Eulerian mean cross‐slope flow is close to zero, and the corresponding fluxes do not describe the correct vertical distribution.