Interdecadal change in sea surface temperature anomalies associated with winter rainfall over South China

摘要

The present study investigates the interdecadal change in winter (January-February-March, or JFM) rainfall over South China and in the South China JFM rainfall—sea surface temperature (SST) relationship by using station observations for the period of 1958-2002, the Met Office Hadley Centre's SST data for the period of 1900-2008, and the ERA-40 reanalysis for the period of 1958-2002. It is found that the relationship between South China JFM rainfall and SST experienced an obvious interdecadal change around the year 1978. The analyses show that the JFM rainfall anomalies during 1960-1977 and 1978-2002 were closely associated with the South China Sea (SCS) SST and El Nino—Southern Oscillation (ENSO), respectively. Moreover, southwesterly anomalies at 700 hPa dominate over the SCS for positive SCS SST anomaly years during 1960-1977 and for El Nino years during 1978-2002, respectively. These wind anomalies, which are associated with the enhancement of the western Pacific subtropical high, transport more moisture into South China, favoring increases in rainfall.