On the seasonal sea surface temperature variations in the tropical Pacific

Abstract

In this paper, we investigated physical processes that control the seasonal variations of sea surface temperature in the tropical Pacific, using an intermediate ocean model. It is found that the westward propagation of sea surface temperature along the equator is attributed to dynamic response of the ocean to the wind (that consists of 3-dimensional temperature advection), whereas the northward propagation of sea surface temperature in the eastern Pacific results from the thermodynamic response of the ocean to the surface heat flux, primarily shortwave radiation that includes the effect of low-level stratus clouds. The remote response of the eastern Pacific sea surface temperature to seasonally varying wind in the western Pacific is of secondary importance, compared to the local wind forcing. The results suggest that the mechanism that controls the seasonal cycle of sea surface temperature is different from that associated with El Nino-Southern Oscillation.