Inter-annual changes of water temperature in the Southern South China Sea's continental shelf: The influence of ENSO on Malaysian waters

Abstract

An extensive amount of data from the World Ocean Database (WOD) that covers the southern South China Sea (SSCS) were analysed to study the long-term trends and variations of the El-Nino Southern Oscillation (ENSO) event. The WOD data were selected from 1951 to 2010, which included the area within 0-10 ºN and 100-117 ºE. El-Nino and La-Nina anomaly results showed that the sea surface temperature anomalies (SSTa) trend of SSCS was higher during offset-El-Nino years and lower during offset-La-Nina years. Besides, the inter-annual vertical water temperature profile revealed that the deepening of the warmer water temperature occurred in February and August of the offset-El-Nino years. Next, analysis of the potential area for coastal upwelling showed that the uplifting of cold water (26 ºC) at the east coast of Peninsular Malaysia (ECPM) occurred during the peak southwest monsoon, whereas at the northwest of Sabah waters (NWSW), it occurred during the offset northeast monsoon. El-Nino suppressed the coastal upwelling at the ECPM due to the intense mixing of warm water during the offset-El-Nino years. Meanwhile, El-Nino enhanced the coastal upwelling in the NWSW due to the establishment of a positive wind stress curl anomaly at the northwest Borneo coast.