Fig. 4: TS-diagrams of time series at the bottom south of Storfjord (F1) and at the shelf break (SB1)
convection is expected to transport heat downwards when plumes drain from the banks northwest of Novaya Zemlya. mean temperature of the plume at the shelf edge was above 0℃. Entrainment of Atlantic water comparable to the process described by Rudels et al. (1994) for the slope
Interannual variability
The ability of Barents Sea water to ventilate the deep Arctic Ocean depends strongly on the salinity of the permanent outflow and the saisonal plumes. At present, the Barents Sea outflow reaches only down to about 1500 m.
The salinity of the cold outflow from Storfjorden was lower in the period 1993/94 than it was in 1991/92 and simultaneously the flow was weaker. Consequently, during 1993/94 the plume was too light to sink below 500 m in the deep basin. Whereas the bottom water salinity varied significantly between the two periods, the TS-range of the Atlantic water remained almost constant. The variation can partly be explained by weaker ice formation and brine release due to warmer atmospheric conditions and higher ice coverage in 1993/1994 than in 1991/1992. An additional cause for the salinity decrease of the plume was the lower salinity of the source water for the convection east of Svalbard in 1993/94.
There is no strong direct river runoff to the Barents Sea, and a main fresh water source is the Norwegian Coastal Current (NCC) which integrates the continental runoff of northern Europe. Within the climate variability of the North Atlantic Oscillation this area is exposed to strong variability of precipitation, with large precipitation during the high NAO of the nineties (Dickson, pers. com.). Water of the NCC spreads northwest of Novaya Zemlya where, through freezing and convection, it is directly involved in the conveyor of the Barents Sea. However, also variations in the ice budget can cause great changes in the surface salinity. Ice import from the Kara Sea and the central Arctic Ocean of 0.05 Sv, as derived from SSM/I data for the winter 1992/93 (Martin and Augstein, 1998), could if mixed downwards considerably decrease the salinity of the Barents Sea outflow.
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