The inversion of the Equatorial Undercurrent in the western tropical Pacific during 1986/1987 El Nino event

摘要

On the basis of time series measurements of winds, currents, temperature and salinity from equatorial current meter mooring and acoustic Doppler current profiler during the PRC/USA joint air-sea interaction studies in the western tropical Pacifc Ocean and sea level data provided by Prof. Wyrtki, analyses are made of the physical process and mechanism for the exceptionally inverse phenomenon (westward) of the Equatorial Undercurrent (EUC) in the western tropical Pacific after entering the mature stage of 1986/1987 ENSO event, and the numerical simulation is also conducted by "cross section" model. The results indicate that the inversion of the EUC is related to that of pressure gradient force near the equator under the influence of non-local permanent westerlies.