ENSO and Short-Term Variability of the South Equatorial Current Entering the Coral Sea

Abstract

istorical section data extending to 1985 are used to estimate the interannual variability of transport entering the Coral Sea between New Caledonia and the Solomon Islands. Typical magnitudes of this variability are ±5?8 Sv (Sv ≡ 106 m3 s?1) in the 0?400-m layer relative to 400 m, and ±8?12 Sv in the 0?2000-m layer relative to 2000 m, on a mean of close to ?30 Sv (relative to 2000 m). Transport increases a few months after an El Niño event and decreases following a La Niña. Interannual transport variability is well simulated by a reduced-gravity long Rossby wave model. Vigorous westward-propagating mesoscale eddies can yield substantial aliasing on individual ship or glider surveys. Since transport variability is surface intensified and well correlated with satellite-derived surface geostrophic currents, a simple index of South Equatorial Current transport based on satellite altimetry is developed.