The large-scale circulation in the Skagerrak; interpretation of some observations

Abstract

Instantaneous velocity observations with high-space resolution at two sections in the Skagerrak has been repeated during the years 1975 to 1977. The velocity observations are presented together with hydrographic data. The mean currents show a cyclonic circulation. Apart from a narrow baroclinic coastal current, the mean velocities generally increase towards the bottom. The mean velocities at the bottom are highest close to and below the sill depth. In the upper layers, the direction of the circulation occasionally changes, whereas in the deeper layers, the cyclonic circulation is present in all the observations. The advective residence time for the water down to 400–500 m in the Skagerrak is some 100 days. The barotropic transport in the circulation has the same magnitude around the Skagerrak and at the eastern part of the sill west of Norway.