Fysisk oseanografiske undersøkelser i sentrale deler av Barentshavet i juli 1979

Abstract

A limited area of the marginal sea ice zone in the Barents Sea was investigated in the period 9-19 July 1979 with the intention of describing the biological production system in the vicinity of an ice edge. This paper describes the physical oceanographic conditions in the observation period. Two main sections, I and II, and three auxiliary sections, A, B and C, were worked out (Fig. 1). Section II was covered twice with 6 days interval between each coverage. All sections were characterized by a homogeneous surface layer of about l0 m. Below this there was a transition layer, which in both sections was most pronounced in the northern part. In section II a tongue of cold Arctic water was penetrating southwards below the transition layer. This tongue was also observed in the sections A, B and C. The second coverage of section II showed that the southern part of the tongue was in process of being mixed with surrounding water masses. During this coverage the surface temperature was 2-4°C higher than during the first coverage. This was due to heating by short wave radiation from the sun and was calculated to be 3.2°C in the upper 10 m. Two anchor stations of duration 30 hours were made at two locations in section II, one in the southern part and one in the northern part. There was insignificant variations in the hydrographical conditions during these 30 hours at both stations. At both anchor stations current measurements were carried out with Gytre current meters. In addition, at the southern anchor station, current was measured for 8 days with 4 Aanderaa current meters suspended from a subsurface buoy. All current measurements showed small velocities, and both speed and direction changed very little with depth.