Observational analysis of the wind-evaporation-SST feedback over the tropical Pacific Ocean

Abstract

Theoretical studies suggested that the wind-evaporation-sea surface temperature (SST) (WES) feedback plays an important role in maintaining the latitudinal asymmetry of the intertropical convergence zone (ITCZ) in the tropical Pacific Ocean. This study examines the geographical distribution of the strength of WES feedback over the tropical Pacific Ocean using multiple long-term observational datasets. The results show that the WES feedback is very weak over the eastern Pacific warm pool and stratocumulus regions, where the strongest latitudinal asymmetry of the ITCZ exists, suggesting that some other mechanisms are responsible for the asymmetry. To the west of 120W, the WES feedback has larger magnitude but is often statistically insignificant. This is because the effect of the air-sea humidity difference tends to offset the wind effect, which is a factor not considered in the original WES feedback theory. Copyright © 2008 Royal Meteorological Society.