A field program is designed to determine the dynamics of the three-dimensional wind driven flow and its impact on the sea surface temperature in the eastern Pacific. The objective is to suggest a revised theory for the North Equatorial Counter Current (NECC) by testing several hypotheses involving a modification to linear Sverdrup theory and the role of the NECC in controlling the location and magnitude of the eastern Pacific warm pool. A two-ship survey will be conducted together with the deployment of surface drifters during the seasonal maximum of the NECC to measure the current, temperature and salinity structure of the upper ocean. The project is contribution to the Climate variability and Predictability Program (CLIVAR) and collaborative with Mexican scientists.