The atmosphere affects the ocean via the wind stresses it imposes on the ocean, by its control of rainfall and evaporation, and by its modulation of net solar and longwave radiative input into the ocean. The oceanic SST and mixed layer depth distributions in turn affect atmospheric winds, cloudiness, and rainfall. In addition, future prediction of SST and mixed layer depth requires an understanding of the entrainment of water from beneath into the mixed layer, and the characteristics of this entrained water. Here we discuss how we plan to obtain an understanding of these processes in the east Pacific.