Eddy momentum and heat ftuxes and their effects on the circulation of the equatorial Pacific Ocean

Eddy momentum and heat fluxes are estimated from three-dimensional arrays of long time-series current meter measurements in the equatorial Pacific near 152W and 110W during 1979 to 1981. Eddies transport eastward momentum away from the equator above the core of the Equatorial Undercurrent; they transport eastward momentum toward the equator below the Undercurrent core. The vertical integral of the eddy momentum flux divergence is equivalent to a westward wind stress of 0.16 dyne cm–2. Eddies transport heat toward the equator at all depths down to 250 m. At 100 m depth and below, the eddy heat flux convergences are remarkably similar at 152W and 110W. Above 100 m, the heat flux convergence at 110W is much larger than that at 152W. The vertical integral of the average eddy heat flux convergence between 152W and 110W is equivalent to a heating of the equatorial region at a rate of 245 W m–2. Lateral eddy viscosities and diffusivities are of order 0.5 to 5 × 107 cm2 s–1, similar to those generally used in numerical models. Eddy coefficients, however, are positive only above the core of the Equatorial Undercurrent and are consistently negative below the Undercurrent core. Fluctuations with periods between 32 and 13 days and centered at 21-day period contribute the bulk of the eddy heat and momentum fluxes