Potential Energy Maxima in the Tropical and Subtropical North Atlantic

Abstract

Expendable bathythermograph records are combined with stability information to provide estimates of the potential energy associated with vertical displacements in the tropical and subtropical North Atlantic thermocline. The geographic distribution of potential energy magnitudes provides a means by which the dynamics implications of thermocline displacements in areas of differing vertical density structures can quantitatively be compared. A broad zonal minimum in potential energy exists along 24?°N in the eastern and western North Atlantic basins. From this minimum potential energy levels increase significantly in magnitude to the north and to a lesser extent to the south with highest values indicated for the boundary-circulation-associated regions of the subtropical gyre. More geographically restricted maxima are found along the flanks of the Mid-Atlantic Ridge and near the Antilles Islands Arc, indicating that topographic influences may be important in addition to what appears predominantly to be a current-related potential energy field. Comparisons of these estimates with observations suggest that the areas of potential energy maxima are associated with significant eddy activity and that the conditions observed during MODE are statistically characteristic of the more quiescent central zone.