The relationship between the cold surge over the NSCS & the ENSO events

Based on the NCEP/NCAR reanalysis and the NOAA sea surface temperature (SST) data, the interannual variation of the cold surge over the northern South China Sea (NSCS) and the relationship between the cold surge over the NSCS and the SST in the equatorial central and eastern Pacific have been investigated. The results show that the occurrence frequency of the cold surge over NSCS has an interannual variation with a significant period of 2-4 years. The interannual variation of the cold surge occurrence frequency is closely related to that of the SST in the equatorial central and eastern Pacific. When the SST anomaly in the equatorial central and eastern Pacific is negative (positive), i.e. when La Niña (El Niño)occurs, the occurrence frequency of the cold surge over NSCS is higher (lower) than normal. When the SST anomaly in the equatorial central and eastern Pacific is negative (positive), the Walker circulation becomes stronger (weaker) than normal. At the same time, the northerly (southerly) anomaly occurs over the Southeast China and its adjacent regions and the convections over South China Sea (SCS) and its adjacent regions are intensified (weakened), which further intensifies (weakens) the Walker circulation. And the numerical experiments verify the above results.