资源环境科技发展态势分析平台

Based on multi-source observational data from 1979 to 2013, we investigate the evolution of the global sea surface temperature anomaly (SSTA) on a quasi-quadrennial cycle and its impact on the seasonal evolution of circulation and precipitation in East Asia. We do this by using principal oscillation pattern analysis and associated correlation pattern analysis, together with numerical experiments from an atmospheric general circulation model. The results indicate that the global SSTA exerts profound impacts on the East Asian climate anomaly, while distinct responses exist between the SSTA developing and decaying stages. From winter to autumn in the developing year, southern China is typically wetter than normal. In the decaying year, however, the precipitation over most parts of East Asia is above normal from winter to spring, and the main rainfall band meandering from the Yangtze River to South Japan is enhanced in summer. During the developing and decaying years, an upper-level anomalous cyclone moves from Northeast Asia to the Tibetan Plateau, and then retreats back. A low-level anomalous cyclone occurs over Northeast Asia in spring, but weakens in summer and then strengthens gradually from autumn to the following summer. An anomalous Philippine Sea anticyclone occurs in winter and spring, but is replaced by an anomalous cyclone in summer before reappearing and persisting from autumn to the decaying year. The abrupt change in circulation patterns in summer of the developing year might be related to the anomalous weakening of the Tibetan Plateau heating. These anomalies can be attributed to the combined effects of the global large-scale heating, regional-scale oceanic forcing, and thermal feedback of the land.