Circulation Characteristics of Winter Rainfall Interannual Variations over South China and Their Response to Preceding Sea Surface Temperature Anomalies

The characteristics of the interannual variability of winter (December–February) precipitation over South China and their association with atmospheric and preceding ocean conditions are analyzed using the observed precipitation data from 160 surface meteorological stations in China, the NCEP/NCAR reanalysis dataset, and the sea surface temperature (SST) dataset from the Met Office Hadley Center. The precipitation tends to be more (less) than the climatology under a southward (northward) shift of the East Asian jet stream, the weakened (strengthened) East Asian trough, and the enhanced (attenuated) transient eddy. The southwesterly winds from the Bay of Bengal and the South China Sea in the front of the southern branch trough favor more precipitation over South China. Further analysis suggests that the preceding SST anomalies (SSTAs) over the tropical Indian Ocean and western tropical Pacific in November have a closer relationship with the southern branch trough and low-level southwesterly winds associated with the variation in precipitation over South China, which could not be well explained by the ENSO-like SSTAs. The correlation coefficient between precipitation over South China and the derived index from the preceding SSTA is 0.44 and reaches a maximum when the SSTA index leads precipitation anomalies by approximately one month, which may act as a potential precursor for wintertime precipitation predictions.