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

Abstract

AbstractAnnual 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°N, 115.5°E, together with satellite and other data, to show the arrivals near z ≈ −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 ≈ −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