Variability in the Atlantic inflow to the Barents Sea based on a one-year time series from moored current meters

Abstract A 1-yr time series from an array of moorings across the Barents Sea Opening was investigated with emphasis on giving a description of the monthly to seasonal variability in the transport of Atlantic water (AW) into the Barents Sea. The results revealed an inflow with large fluctuations in both time and space, and showed that the circulation implied in the hydrographic conditions, with inflow in south and outflow in north, was not always the case. The flow might occur as a wide Atlantic inflow, as inflow and recirculation in narrow bands side-by-side, or as an outflow covering the occupied section all the way south to 72°N. The variability in the inflow of AW was, to some extent, determined by two factors: (1) the temporal variability in the deeper parts (i.e., below 300 m), and (2) the spatial variability in the northern boundary of the inflow. The volume transport across the section between 71°15′N and 73°45′N was calculated and gave a net inflow of AW of 2 Sv (1 Sv=10 6  m 3  s −1 ). In some periods, the inflow was reversed, and there was an outflow from the Barents Sea towards the Norwegian Sea. On a monthly basis, the transport fluctuated over a range of almost 10 Sv. The variability was, in some periods, clearly linked to the local atmospheric pressure fields, although additional forces were needed to account for the total flux. In some periods, the correlation between the local surface atmospheric pressure and volume flux was poor. A mesoscale eddy, present for about one month, was observed. A seasonal signal, consistent with the generally accepted seasonal cycle for the Barents Sea, was not found. However, the current measurements indicated a change in the flow field between summer and winter. During the winter, the frequent passing of atmospheric lows intensified the currents, producing a structure with strong lateral velocity gradients and a distinct, surface intensified, relatively high-velocity core of inflow and recirculation further north. During the summer, the weaker winds caused the inflowing area to be wider, the horizontal shear and the velocities to be lower, and there were two cores of inflow.