Impact of Preceding Summer North Atlantic Oscillation on Early Autumn Precipitation over Central China

AbstractThis study examined the impact of the preceding boreal summer (June–August) North Atlantic Oscillation (NAO) on early autumn (September) rainfall over Central China (RCC). The results show that a significant positive correlation exists between the preceding summer NAO and the early autumn RCC on the interannual timescale. In order to understand the physical mechanism between them, the role of ocean was investigated. It was found that the strong summer NAO can induce a tripole sea surface temperature anomaly (SSTA) in the North Atlantic; this SSTA pattern can persist until early autumn. The diagnostic analysis showed that the tripole SSTA pattern excites a downstream Atlantic-Eurasian (AEA) teleconnection, which contributes to an increase in RCC. The circulation anomalies related to SSTA caused by the weak NAO are opposite, so the RCC is less than normal. The results imply that the preceding summer NAO may be regarded as a forecast factor for the early autumn RCC.