Shelf-Basin Exchange across the Western Arctic Boundary Current

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The halocline of the Arctic Ocean tends to isolate the sea ice on the surface of the ocean from the heat carried into the ocean with flows of warm Atlantic Water. Changes in the structure or persistence of this halocline will, thus, have an important influence on the rate of change of sea ice cover in the Arctic and, consequently, global climate. How this halocline is maintained is an open question, but one theory strongly implicates the lateral flux of cold waters from the shelves surrounding the Arctic Ocean.In 2002-2004 a high-resolution mooring array was situated across the shelfbreak and upper slope of the Beaufort Sea, east of Barrow Canyon. The array consisted of vertically profiling conductivity/temperature/ depth sensors (CTD Moored Profilers), combined with Acoustic Doppler Current Profilers and profiling acoustic current meters. The moorings were spaced only 5 km apart, and represent the first time that the boundary current system in the Arctic has been measured at the scale of the Rossby radius of deformation using moorings. The array returned over 3,000 synoptic cross-slope CTD sections and 18,000 absolute velocity sections, over all of the seasons. Funds are provided to carry out the analysis of this data set. The principal investigators' central hypothesis is that the dynamics of the boundary current system dictates, to first order, the transfer of mass and properties from the shelf to the open ocean, which, in turn, is thought to maintain the upper halocline of the western Arctic. The analysis effort will focus upon upwelling dynamics, eddy formation, and secondary circulation and ageostrophic dynamics.