Isopycnal Analysis of Near-surface Waters in the Norwegian-Barents Sea Region

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The waters of the Nordic and Barents Seas exhibit very large variations in temperature and salinity. In order to distinguish between dynamical and thermodynamical effects we use isopycnal analysis to map the depths of these surfaces on the one hand, and property change along these surfaces on the other. Analysis of the 27.7 to 27.9 isopycnal surfaces show that these generally shoal to the north as expected, towards the Greenland Sea in the west and the Barents Sea in the east. However, geostrophically speaking this bowl-like shoaling pattern implies a retroflection and anticyclonic circulation in the Lofoten Basin. Identifying the processes responsible for this pattern is of fundamental importance to a proper understanding of the dynamics of the region as well as to identify transport pathways of physical, chemical and biological properties. The isopycnal analysis also reveals a conspicuous T/S-anomaly maximum in the Lofoten Basin, which appears to result from convective heat losses and downward mixing of saline waters to deeper isopycnal surfaces where they then appear as warm salty water.