The ocean and the atmosphere are coupled through the exchanges of momentum, heat, and water. In situ measurements of these exchanges are sparse and uneven. Spaceborne sensors provide the only mean to monitor these exchanges at sufficient spatial and temporal resolution to study global climate changes. The fluxes of momentum and kinetic energy are resulted from wind shear which can be monitored by spaceborne microwave scatterometers. The major components of heat fluxes are shortwave radiation from the sun and latent heat carried by evaporation. Shortwave radiation has been estimated from cloud data compiled by the ISCCP, and was derived directly from observations of ERBE, and can be estimated by future sensors such as CERES. Various methods to estimate evaporation have been proposed, using, mainly, integrated water vapor, wind speed, and sea surface temperature from microwave and infrared radiometers. The water flux is the difference between precipitation and evaporation. Estimation of precipitation at visible, infrared, and microwave wavelengths have been attempted, and TRMM is the latest endeavor. The status and shortfalls of spacebased estimation of these fluxes will be summarized and assessed in this study. The data availability at present, and data potential in the future will be described. The impact of these spacebased estimation on the study of seasonal-to-interannual variability of the tropical Pacific (El Nino) will be demonstrated, as an example