资源环境科技发展态势分析平台

The present study investigates the diversity of the La Nina decaying phase and the corresponding spring and summer precipitation anomalies over the eastern China. Based on the differences in sea surface temperature anomaly (SSTA) evolution during the La Nina decaying phase, 18 La Nina events in the period 1961-2016 are classified into three types-namely, the persistent type (P-type), the re-intensified type (R-type), and the fast-decay type (F-type). Precipitation responses over eastern China during the decaying spring and summer of the three types of La Nina present significant differences. For the R-type La Nina decaying spring, the enhanced precipitation appears over northeastern China but significant suppressed precipitation anomalies are observed elsewhere, particularly in Yellow River basin, the Yangtze River basin, and southeastern China. Significant negative precipitation anomaly appears over northeastern China in both P-type and F-type La Nina decaying spring. In the decaying summer, for P-type La Nina, dry anomalies are apparent in southern and northern China. For R-type La Nina, negative rainfall anomalies are notable in northeastern China, the Hetao region, and the middle reaches of the Yangtze River basin. For F-type La Nina, significant negative rainfall anomalies are found over the Yangtze River basin and parts of northern China. The responses of the large-scale circulation anomalies to the distinct SSTA patterns of the different types of La Nina are responsible for the diversity of rainfall anomalies over eastern China. The precipitation anomaly pattern in eastern China is closely associated with the different types of La Nina decay, and it is seasonal-dependent. These two aspects should be taken into account when conducting seasonal predictions of spring and summer rainfall anomalies over eastern China using El Nino-Southern Oscillation as a predictor.