资源环境科技发展态势分析平台

The El Nino-Southern Oscillation (ENSO) has an intimate relationship with Asian summer monsoon precipitation. Previous study pointed out that the most recent 2015-2016 El Nino event is tied with the 1997-1998 and 1982-1983 El Nino events as the strongest event since 1950, which may result in catastrophe in Asian monsoon region. Therefore, in this article, we mainly focus on the anomalous precipitation pattern in the Pan-Asian monsoon region during MJJ 2016 and its impact factors. Results show that the summer precipitation anomalies display a meridional tripole pattern from north to south in the Pan-Asian monsoon region during 2016. This pattern indicates that the anomalous increased rainfall is located over the middle-lower reaches of the Yangtze River valley-East China Sea (ECS) and the tropical eastern Indian Ocean-western Maritime Continent, while the anomalous decreased rainfall is located over the South China Sea (SCS)-Philippine Sea. Results suggest that the preceding winter and spring ENSO and the simultaneous summer Maritime Continent sea surface temperature (SST) are the primary impact factors of the pattern of tripole precipitation anomalies in the Pan-Asian monsoon region during MJJ 2016. The preceding ENSO can intensify the western North Pacific subtropical high (WPSH), which results in the anomalous decrease in precipitation over the Indo-China Peninsula-Philippine Sea. Meanwhile, more moisture is transported from the northwestern flank of WPSH to the Yangtze River valley-ESC to increase rainfall. In the ENSO decaying summer, the Maritime Continent SST anomalous warming induces an anomalous convergence in situ, which increases the local precipitation. Later, this warming can intensify the WPSH through the local meridional circulation. The north Indian Ocean SST, including Arabian Sea and Bay of Bengal, also has a high relationship with tripole precipitation pattern, but it cannot induce this tripole rainfall pattern, which establishes the linkage through the extending WPSH.