Surface fluxes and their influence on sea surface temperature in the western equatorial Pacific during the Coupled Ocean-Atmosphere Response Experiment

Abstract

Surface fluxes in the western equatorial Pacific warm pool region and their influence on sea surface temperature (SST) variability were investigated for the period November 15, 1992, to February 15, 1993, during the Intensive Observing Period of the Coupled Ocean-Atmosphere Response Experiment (COARE). A blended flux data set was developed using a "reanalysis" of surface meteorology from the European Centre for Medium-Range Weather Forecasts (ECMWF), turbulent flux components from the COARE bulk flux algorithm, and shortwave radiation and precipitation estimates from satellite remote sensing. Comparison with in situ fluxes from the center of the warm pool showed that the blended fluxes captured variability associated with the intraseasonal oscillation (ISO) while the fluxes produced by ECMWF did not. The influence of surface forcing on SST was assessed by comparing the observed SST tendency to that produced by a one-dimensional model forced by the blended fluxes. On the ISO timescale, SST changes in a substantial portion of the warm pool were found to be dominated by local surface forcing, although significant contributions from other processes (e.g., horizontal advection) were not ruled out. The results emphasize the fact that high-quality surface fluxes are essential to developing accurate predictions of SST variability in the warm pool region. Copyright 2000 by the American Geophysical Union.