Upper equatorial Pacific Ocean current and salinity variability during the 1996-1998 El Niño-La Niña cycle

摘要: The recent El Nino–La Nina cycle exhibited striking patterns of current and salinity variability in the upper equatorial Pacific Ocean. This evolution is described from mid-1996 through 1998 using a remarkable data set 35 meridional conductivity-temperature-depth (CTD)/acoustic Doppler profiler (ADCP) sections along with buoy data. sections, nominally 8°S to 8°N between 165°E 95°W, were occupied over course 27 months. A wide range was sampled currents that appeared or disappeared some time during cycle, including an equatorially trapped eastward surface current, Equatorial Undercurrent, northern branch South Current, North Countercurrent. Basin-wide, interannual changes ocean pycnocline zonal transports as large 64±32×106 m3 s−1. Changes structure included deep fresh mixed layer central built up Nino then disrupted by upwelled salty water onset La Nina, very observed eastern late Nino, reduction strength gradient within one third usual value Nino. Finally, above thermocline 5°S 5°N well correlated rate change warm-water volume west individual CTD/ADCP sections.