Rothstein 9613363 A mesoscale ocean data assimilation will be developed for the Coupled Ocean Atmosphere Response Experiment (COARE) of the Tropical Ocean Global Atmosphere (TOGA) program to produce a dynamically consistent atlas of oceanic fields to be made available to all COARE Investigators and then use this atlas to investigate upper ocean physical processes in warm pool of the western tropical Pacific Ocean. In particular, the importance of salinity advection within the thermocline and the influence of the three-dimensional circulation on mixed layer evolution will be assessed. Finally, the evolution of energetic sub- mesoscale eddies during equatorial jet spin-down will studied.