Temporal and spatial variabilities of the South China Sea surface temperature anomaly

Abstract

In this study we use the National Centers for Environmental Prediction (NCEP) monthly sea surface temperature (SST) fields (1982-1994) to investigate the temporal and spatial variabilities of the South China Sea (SCS) warm/cool anomalies. Three steps of analysis were performed on the data set: ensemble mean (T∼), composite analysis to obtain the monthly mean anomaly relative to the ensemble mean (T), and empirical orthogonal function (EOF) analysis on the residue data relative to (T) +(T∼). The ensemble mean SST field (T) has a rather weak horizontal gradient: 29°C near the Borneo coast to 25°-26°C near the southeast China coast. Two areas of evident SST anomalies were found in the monthly T∼ variation: west of Borneo-Palawan islands (WBP) and southeast of the southern Vietnam coast (SVC). Four patterns, monsoon and transition each with two out-of-phase structures, were found. During the spring-to-summer transition (March to May) the warm anomaly is formed in the northern SCS with T∼ > 1.8°C located at 112o-119°30'E, 15°-19°30'N. During the fall-to-winter transition (October to November) the northern SCS (north of 12°N) cool anomaly is formed in November with f