Temporal and Spatial Structure of the Equatorial Deep Jets in the Pacific Ocean*

Abstract

Abstract The spatial and temporal structure of the equatorial deep jets (EDJs) in the Pacific Ocean is investigated using CTD station data taken on the equator from 1979 through 2001. The EDJs are revealed in profiles of vertical strain, ξz, estimated from the CTD data in a stretched vertical coordinate system. The majority of synoptic meridional sections were occupied over an 8-yr span west of the date line. Two-decade equatorial time series are available at both 110°W and 140°W. Analysis shows the expected equatorial trapping of ξz but yields little new detailed information about the EDJ meridional structure. Analysis of the equatorial data yields novel results. The EDJs are most easily seen in the eastern Pacific (at and east of 140°W). There, they may be isolated from the influence of higher-frequency Rossby waves generated by surface forcing. Spectral analysis of equatorial ξz profiles shows a significant and coherent peak at 400-sdbar vertical wavelength (with No = 1.56 × 10−3 s−1) from 95°W to 142°...