ON THE DYNAMICS OF THE LARGE-SCALE CIRCULATION OF THE SKAGERRAK

Characteristic features of the large-scale hydrography of the Skagerra k are reviewed. A dominant overall feature is the deep reaching cyclon ic circulation. The modelling of the circulation in the Skagerrak, as part of the current pattern in the North Sea is discussed. Simplified mechanistic models are derived to elucidate the governing dynamics. Qu alitative and quantitative implications of these models are compared t o what is known from observations. It is concluded that the basic cycl onic circulation in the area is to a large extent forced by the mixing of high-saline deep water into the outflowing low-saline surface wate r of Baltic origin. The time-dependent part of the motion, on the othe r hand, is probably an effect of the local wind as well as of the wind over the rest of the North Sea. In both cases the topography, viz. th e existence of the Norwegian Trench, plays a crucial role.