Moored Surface Wind Observations at Four Sites along the Pacific Equator between 140° and 95°W

Abstract

Mooted surface wind measurements were recorded along the Pacific equator at 140°, 124°, 110°, and 95°W during portions of 1980?85. Minimum record length is one year. The annual mean and monthly mean westward speeds at 110°W were about 1.5 m s?1 higher during the year preceding the 1982?83 El Niño than in the year following this event. The annual cycle, which moved westward at ≈0.8 m s?1, consisted of weak westward and northward speeds in February?April and vice versa in September?October. The spectral slope between 5-day and 0.05-day periods was ?1.5. The rms amplitude of the 95% statistically significant diurnal period oscillation was 0.3 m s?1, and the meridional component was nearly twice as large as the zonal component. The diurnal period wave was coherent (at the 95% confidence level) between 95° and 124°W with westward phase propagation of about 138 m s?1. No statistically significant (at the 95% confidence level) spectral peak was found in the 40- to 50-day intraseasonal period band. The surface zonal ocean current component, which reached approximately 0.5 and ?0.5 m s?1 in April and October, respectively at 110°W, influenced the surface wind stress computed from the quadratic bulk aerodynamic formulation by 10%?20%.