9531874 Spall This project is a contribution to the modeling component to be carried out as part of the Atlantic Circulation and Climate Experiment (ACCE) under the World Ocean Circulation Experiment (WOCE). The focus will be on upgrading existing isopycnal models, data assimilation, and integrating different types of regional models. Comparisons will be made among different modeling approaches in order to assess the strngths and weaknesses of each, and to determine the best overall approach for including ocean variability in climate modeling. Particular attention will be paid to assimilating, into the models, data from the field phase of ACCE, as well as from historical data bases. In this particular project, the PI will focus on the physics that control the time dependent spreading of intermediate and deep waters away from their source regions in the subpolar gyre, and the influences of these water masses on the basin-scale upper ocean flow and Sea Surface Temperature. Specific influences include baroclinicity, bottom topography, isopycnal and diapycnal mixing, eddy fluxes, and time dependence in partitioning the waters into boundary current transports and interior recirculation gyres.