Department of Earth System Science

The annual cycle of sea surface temperature (SST) in the eastern Pacific warm pool and its relation to Central America gap winds are examined in this study. Locally enhanced annual harmonics of SST are found underneath the regions where the Tehuantepec and Papagayo gap winds blow. The SSTs underneath the Tehuantepec gap wind undergo larger annual variations than those underneath the Papagayo gap wind. This suggests that the Tehuantepec gap wind has a stronger influence on the annual cycle of SST than the Papagayo gap wind. A series of ocean model experiments are performed to demonstrate the enhancement effect of the gap winds. Further heat budget analyses of the experiments show that the gap winds increase the amplitude of the SST annual cycle primarily by enhancing the vertical entrainment process in the ocean. The thermal forcing effect of the gap winds is less important in modulating the SST annual cycle.