Collaborative Research: A Study of the Extension of the North Atlantic Current and Pathways of Exchange

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9531878 Rossby As a contribution to the Atlantic Circulation and Climate Experiment (ACCE) of the World Ocean Circulation Experiment (WOCE), the Pis in this project will seek to identify the pathways of the warm-water North Atlantic Current (NAC) and the sites and mechanisms of frontal exchange across it using approximately 80 isopycnal RAFOS floats to be launched at various locations in the vicinity of the NAC. Specific objectives include: (1) exploring the structure of the front which separates the cold, fresh subpolar water to the north and the warm, saline subtropical water to the south, and (2) attempting to quantify the mechanisms and rates of exchange between the two gyres. In conjunction with the field program of Drs. Bower and Richardson of the Woods Hole Oceanographic Institution, they will also expand the study of the bifurcation of the NAC as it enters the eastern North Atlantic. The North Atlantic Current (NAC) is recognized as a crucial element of the meridional overturning cell, both as the primary northward-penetrating upper-ocean current and as a region where thermodynamic exchange occurs between the subtropical and subpolar gyre. Its character changes from an intense, topographically controlled jet in the western boundary, to a less- defined, perhaps filamented eastward flow after veering east north of the Flemish Cap. It is not clear whether the NAC is a discrete front that translates north and south, a collection of fronts, or simply a broad swath of eastward flow, nor is its fate fully understood. Although most of the flow is to the north and towards Europe, some recirculation occurs as well, and this partitioning of pathways is important in attempting to understand and quantify the controlling factors of the overturning cell.