Distinct Evolution of Sea Surface Temperature over the Cold Tongue Region in South China Sea during Various El Niño Events

Min Wu,Li Qi

doi:10.3390/atmos12121689

Abstract

This study investigates the evolution of the sea surface temperature (SST) over the cold tongue (CT) region in the central South China Sea (SCS) during various El Niño events. A significant and distinct double-peak warming evolution can occur during EP El Niño and CP El Niño events, with the former being more remarkable and robust than the latter. Further analyses show that the weak and insignificant CT SST anomaly in CP El Niño events is influenced by some CP El Niño events in which the warm sea surface temperature anomaly (SSTA) is located west of 175° E (WCP El Niño). The response of CT SSTA mainly depends on the warm SSTA location of CP El Niño. The different corresponding mechanisms in winter, spring and summer are discussed respectively in this work. Further analysis reveals that the weak and insignificant SST anomaly over the CT region in CP El Niño events is caused by the faint SSTA response during the WCP El Niño events. The results of this study call attention to the response of the SCS climate in both atmosphere and ocean to the diversity of ENSO, especially the CP El Niño.

Highlights

Many studies have demonstrated that the Indo-Pacific warm pool has a great influence on the global climate regime, where the energy released by deep convection is always considered as the source of the global circulation system [1,2]
The intensity of the sea surface temperature anomaly (SSTA) is much weaker in CP El Niño events relative to EP El Niño events
In the first peak during winter, a dramatic warm SSTA is observed over the cold tongue (CT) region in EP El Niño events; the associated warm SSTA is greater than 0.5 ◦ C

Summary

Introduction

Many studies have demonstrated that the Indo-Pacific warm pool has a great influence on the global climate regime, where the energy released by deep convection is always considered as the source of the global circulation system [1,2]. The central part of SCS, with a high sea surface temperature (SST) above 26 ◦ C, is one of the most frequent genesis locations of tropical cyclones over the western North Pacific [3]. Interannual variations of SCS SST play a crucial role in weather and climate over local and surrounding regions. From spring to summer, the SST in central SCS does not warm monotonically as the solar radiation increases. It begins to cool down after the southwest monsoon onset. Wyrtki [4] first pointed out that the CT exerts a vital role on the interannual variations of the SCS climate

Methods

Results

Conclusion