Asymmetric response of the South China Sea SST to El Niño and La Niña

Abstract

The interannual variability of the sea surface temperature (SST) in the South China Sea (SCS) is investigated according to its relationship with El Nino/La Nina (EN/LN) using monthly products from ICOADS. The SCS SST bears two peaks associated with EN/LN and shows the asymmetric features. Coinciding with the mature phase of EN/LN, the first SST warming/cooling peaks in December(0)-February(1) (DJF(1)) and centers in the southern part. The major difference is in the amplitude associated with the strength of EN/LN. However, the SCS SST anomaly shows distinct difference after the mature phase of EN/LN. The EN SST warming develops a mid-summer peak in June-August(1) (JJA(1)) and persists up to September-October(1), with the same amplitude of the first warming peak. Whereas the LN SST cooling peaks in May(1), it decays slowly until the end of the year, with amplitude much weaker. Comparing with SST and atmospheric circulations, the weak response and early termination of the second cooling is due to the failure of the cyclonic wind anomalies to develop in the northwest Pacific during JJA(1).