Relationship between ENSO and Winter Rainfall over Southeast China and Its Decadal Variability

In this study, the relationship between El Nino-Southern Oscillation (ENSO) and winter rainfall over Southeast China (SC) is demonstrated based on instrumental and reanalysis data. The results show that ENSO and SC winter rainfall (ENSO-SC rainfall) are highly correlated and intimately coupled through an anomalous high pressure over the northwestern Pacific. In mature phase, El Nino (La Nina) events can cause more (less) rainfall over SC in winter. Due to the persistence and spring barrier of ENSO, SC winter rainfall has potential predictability of about half a year ahead with ENSO as a predictor. Besides, the ENSO-SC rainfall relationship exhibits decadal variability, closer before the early 1970s (0.47) and after the early 1990s (0.76), but weaker (0.12) between these times. In different periods, atmospheric teleconnection patterns have large differences and the predictability of SC winter rainfall also changes dramatically. For the most recent 20 years, the ENSO-SC rainfall relationship is closest and the prediction of SC winter rainfall anomalies based on ENSO is most creditable. In addition, the causes and mechanisms of the decadal modulation of the relationship between ENSO and SC winter rainfall need to be further studied.