Contribution of intraseasonal oscillation to long-duration summer precipitation events over southern China. Issue 1 (2nd January 2017) - LIU, Ge
Abstract: Precipitation events spanning multiple days may have consequences different from those limited to a single day. In the present paper, the authors analyze circulation anomalies and precursory signals associated with long-duration (over 14 days) summer precipitation events over southern China. The results show that the over-14-day precipitation events are induced by an anomalous lower-tropospheric (850-hPa) cyclone over the South China Sea (SCS) and southern China. The anomalous westerly winds to the south of the anomalous cyclone can be traced to north of New Guinea 30 days before. To the north of anomalous westerly winds, anomalous easterly winds appear later. The anomalous westerly and easterly winds form a cyclonic anomaly, moving northward and slightly westward during the following days and eventually controlling the SCS and southern China. The northward movement of anomalous westerly and easterly winds can also be found in the 30–60-day filtered wind field. This implies that the northward propagating 30–60-day intraseasonal oscillation from the equatorial western Pacific has an important contribution to over-14-day precipitation events over southern China.