On the variability of Atlantic Influence in the Norwegian and Barents Seas

Abstract

Variability in Atlantic influence in the regime of the Norwegian Atlantic current and its branches in the Barents Sea are studied by establishing time series of mean temperature and salinity values in four hydrographic sections. A section Svinøy-NW was worked in December from 1951 to 1968 and in January from 1952 to 1973. In the Barents Sea three sections have been worked in August-October, one between Fugløya and Bjørnøya since 1964, one northward from Vardø along 31°13'E since 1953 and one northward from the Sem Islands along 37°20'E since 1956. Mean values of temperature and salinity have been established for parts of the sections in the depth intervals 0-50, 50-100 and 100-200 m. Three-year running means have been prepared to reduce the effect of year-to-year fluctuations. The three- year running means of the time series showed the same long-term trends in all three depth intervals. Similar features were found in all the sections. The most outstanding feature in the time series is a decrease in both temperature and salinity during the period 1972-79. This trend agrees with observations made in the Rockall Channel, the open northeast Atlantic and Norwegian Sea. However, the longterm trends indicate a time lag of about three years between the Rockall Channel and the Barents Sea sections.