Rossby Waves and Eddies Observed at a Temperature Mooring in Northern South China Sea

Abstract

Annual Rossby waves in northern South China Sea had previously been studied using altimetry and model data; however, how they connect to subsurface temperature fluctuations has not been examined. This study analyzed a 22-month, surface to -500-m temperature time series at 18.3 degrees N, 115.5 degrees E, together with satellite and other data, to show the arrivals near z approximate to -300 m and deeper cool (warm) Rossby waves after their generation near the Luzon Strait in winter (summer). Temperature fluctuations with time scales of a few weeks, and with maximum anomalies near z approximate to -100 m, were also found embedded in the smooth Rossby waves and caused by propagating eddies. Eddy fluctuations and propagation past the mooring were of two types: southwestward from southwestern Taiwan, triggered by Kuroshio intrusion that produced anticyclone-cyclone pairs in late fall and winter, and eddies propagating westward from Luzon forced by annual anomalies of wind stress curl and Kuroshio path in the Luzon Strait