Hydrographic investigation of the Northern Kattegat front

Abstract

The Northern Kattegat front separates Kattegat surface water or around 26 PSU and Skagerrak water of around 34 PSU. The front plays an important role in the water exchange between Kattegat and Skagerrak, and consequently it is also important for the exchange of dissolved and suspended matter such as nutrients, organic material and Gelbstoff. In order to investigate the dynamics of the Northern Kattegat front two surveys were performed, one in the period 2–12 March, 1992 and in one in the period 21 September–2 October, 1992. Vertical profiles of temperature, salinity and current were measured along cross-sections. The data from the two surveys and the analyses of the data concerning the dynamics of the Northern Kattegat front are presented. First, a conceptual model of the current dynamics, based mainly on Stigebrandt, A. (1987) ( Tellus, 39A, 170–177), is proposed, where the front is considered to be a ‘rotational baroclinic control’ guiding the current in the Kattegat. The model is evaluated on the basis of the two surveys. Secondly, an equation describing the outflow from the Kattegat to the Skagerrak is derived and evaluated.