Large Scale Forcing and Oceanic Response

Abstract

Abstract : LONG-TERM GOALS The long-term goal is to observe, understand, and model air-sea interaction, upper ocean variability, and links between the upper ocean and the interior over a wide range of environmental conditions. OBJECTIVES. The goal of the work in the eastern North Atlantic done as part of the Subduction Experiment is to observe the structure and dynamics of the Ekman layer and learn how, over an area such as the eastern end of the Bermuda-Azores high pressure cell, the convergence of the Ekman layer carries water from the surface into the main thermocline. The objectives of the observational component have been to: 1) make high quality, direct observations at widely spaced surface moorings in the Subduction and ASTEX (Atlantic Stratocumulus Transition Experiment) region of the surface forcing (wind stress and buoyancy flux) fields; 2) observe the oceanic velocities and temperatures at these sites, resolving the vertical structure of the upper ocean and its temporal variability over two annual cycles; 3) collect sufficient information about the surface forcing and upper ocean structure at sites between the moorings to allow extrapolation over the whole Subduction region of the description of the mixed layer response to atmospheric forcing; 4) observe at a site central to Subduction the response of the thermocline and the interior of the ocean as well as of the mixed layer. The objectives of modeling done in conjunction with the analysis of the data are to gain further understanding of how materials and properties are transferred from the mixed layer into the ocean interior in regions of Ekman convergence, of the role of large scale variations in atmospheric forcing in subduction, and of vertical transfers in strong frontal regions.