9529794 Leaman In conjunction with companion projects by Drs. S.Riser of the University of Washington and R. Schmitt of the Woods Hole Oceanographic Institution, approximately 145 profiling P-ALACE (Profiling Autonomous Lagrangian and Circulation Explorer) floats (at least half of them with salinity) will be used to study specific water-mass transformation processes in the tropical and subtropical Atlantic as part of the Atlantic Circulation and Climate Experiment (ACCE). The basin-wide grid will be used to provide relatively uniform sampling to track upper layer salinity and heat content changes throughout the basin. Higher resolution arrays will be deployed in important local regions where water masses such as the high-salinity Subtropical Underwater (Leaman), relatively uniform 18-degree water (Riser) are formed or transformed, or where important air-sea exchanges are highly variable such as under the ITCZ (Inter-Tropical Convergence Zone) (R. Schmitt). The higher-resolution will allow tracking of seasonal and interannual changes in the volume and structure of the upper ocean features, and relate these to modeled/observed estimates of surface heat and fresh water fluxes. Analysis of these data will provide time series of three- dimensional maps of the velocity, temperature, and salinity fields within the upper 1500 m of the tropical and subtropical gyres over the duration of the ACCE field experiment. Additionally, statistical analyses will provide spatial distributions of mean circulation and quantities like eddy kinetic and potential energies, and eddy mixing, in addition to the flux estimates. These gyre-wide estimates will provide strong constraints for the future climate models that must be developed to adequately include the physics of the tropical and subtropical Atlantic, particularly the fresh water budget. ***
