Impacts of Different Onset Time El Niño Events on Winter Precipitation over South China

Winter precipitation over South China tended to be much higher than normal for the spring El Ni&ntilde
o events during 1979&ndash
2016. For the spring El Ni&ntilde
o events, the meridional and zonal circulations served as a bridge, linking the warmer sea surface temperature (SST) in the eastern equatorial Pacific (EEP) and South China winter precipitation. This possible physical process can be described as follows: During boreal winter, a positive SST anomaly in the EEP was concurrent with strong anomalous convection activity over South China via anomalous Walker circulation, an anomalous Hadley Cell along 110&deg
&ndash
130&deg
E, and a zonal westward teleconnection wave train pattern at 700 hPa in the Northern Hemisphere. In addition, an anomalous pumping effect at 200 hPa contributed to the convective activity. Meanwhile, the western Pacific subtropical high moved southwards and strengthened at 500 hPa, and abnormal southwesterly winds brought plentiful water vapor to South China at 850 hPa. All these factors favored an increase in precipitation over South China. For the summer El Ni&ntilde
o events, the aforementioned anomalies were weaker, which resulted in a precipitation close to normal over South China.