9417140 Proehl In this project, the PIs will apply modeling techniques to some new ideas about generation mechanisms for Tropical Instability Waves (TIW), which are dramatic oscillations seen from satellites in the sea surface temperature (SST) front in the near-equatorial zones of both the Pacific and Atlantic Oceans. They are responsible for significant equatorward heat fluxes which counteract a large fractioin of kthe cooling due to equatorial upwelling. The focus of this study will be the effects of the critical surface (where the wave phase speed equals the mean flow speed) and the SST fronts on the stability of the TIW. Recent data obtained in the Tropical Instability Wave Experiment (TIWE) will be used to compare model results with the observed behavior of the waves. ***