Recirculation in the Fram Strait and transports of water in and north of the Fram Strait derived from CTD data

[摘要] The volume, heat and freshwater transports in the Fram Strait are estimatedfrom geostrophic computations based on summer hydrographic data from 1984,1997, 2002 and 2004. In these years, in addition to the usually sampledsection along 79° N, a section between Greenland and Svalbard wassampled further north. Quasi-closed boxes bounded by the two sections andGreenland and Svalbard can then be formed. Applying conservation constraintson these boxes provides barotropic reference velocities. The net volume fluxis southward and varies between 2 and 4 Sv. The recirculation of Atlanticwater is about 2 Sv. Heat is lost to the atmosphere and the heat loss fromthe area between the sections averaged over the four years is about 10 TW.The net heat (temperature) transport is 20 TW northward into the ArcticOcean, with large interannual differences. The mean net freshwater addedbetween the sections is 40 mSv and the mean freshwater transport southwardacross 79° N is less than 60 mSv, indicating that most of the liquidfreshwater leaving the Arctic Ocean through Fram Strait in summer is derivedfrom sea ice melt in the northern vicinity of the strait.In 1997, 2001 and 2003 meridional sections along 0° longitude weresampled and in 2003 two smaller boxes can be formed, and the recirculation ofAtlantic water in the strait is estimated by geostrophic computations andcontinuity constraints. The recirculation is weaker close to 80° Nthan close to 78° N, indicating that the recirculation is mainlyconfined to the south of 80° N. This is supported by the observations in1997 and 2001, when only the northern part of the meridional section, from79° N to 80° N, can be computed with the constraints applied.The recirculation is found strongest close to 79° N.

[学科分类] 海洋学与技术