Volume and Heat Transports to the Arctic Ocean Via the Norwegian and Barents Seas

Abstract

The main aim of this paper has been to present a holistic view of the Atlantic water flow along the Norwegian Coast and into the Barents Sea. It has focused on the period starting in the mid-1990s, with simultaneous arrays of moored current meters in the Svinoy section and the Barents Sea Opening. These detailed measurements have provided the bases for improved estimates of means and variations in fluxes, and their forcing mechanisms. Mean volume and heat fluxes associated with Atlantic water in the Norwegian Atlantic Slope Current (NwASC) are 4.3 Sv and 126 TW respectively for the Svinoy section, showing no significant trends, and 1.8 Sv and 48 TW for the Barents Sea Opening, where positive trends have been found in both measures. These estimates are probably higher than the long-tem mean, since hydrographic data along the Norwegian Coast show that the periods of direct current measurements are the prolongations of a period that started in the late 1970s, since when Atlantic water has become warmer and saltier. The close resemblance, throughout the record, between temperature variations in the Kola section and the AMO-index back to the early 20 century illustrates the importance of large-scale longterm variations in the Barents Sea system. Although the magnitudes of these variations are relatively small in comparison with inter-annual variations, other studies have shown them to be of major importance for ecosystem changes (ACIA, 2005). 2 The different forcing effects of the NwASC and the Atlantic inflow to the Barents Sea to similar atmospheric systems are noted. The results strongly suggest that the relative distribution of the Norwegian Atlantic Current entering the Barents Sea and passing through the Fram Strait is very sensitive to storm tracks. Thus, changes in the predominant storm tracks may trigger major changes, including feedback mechanisms, for the Barents Sea climate and the heat budget of the Arctic Ocean.