文献类型：期刊文献

英文题名：Differences in Pre-Flood Season Rainfall in South China between Spring and Summer El Nino Events

作者：Fan, Lingli[1];Xu, Jianjun[1];Li, Junjie[1]

机构：[1]Guangdong Ocean Univ, South China Sea Inst Marine Meteorol, Coll Ocean & Meteorol, Zhanjiang, Peoples R China

年份：2020

卷号：58

期号：2

起止页码：144

外文期刊名：ATMOSPHERE-OCEAN

收录：SCI-EXPANDED(收录号：WOS:000544560400001)、、WOS

基金：This study was funded by a National Plan on Key Basic Research and Development [grant number 2018YFC1506002] and an Undergraduate Innovative Experiment Project [grant number 201710566005].

语种：英文

外文关键词：spring El Nino; summer El Nino; pre-flood season precipitation; South China

外文摘要：The El Nino-Southern Oscillation (ENSO) plays an important role in pre-flood season (PFS) precipitation over South China. In this work, the analysis of observational and reanalysis data shows that PFS precipitation is closely related to the onset time of El Nino events. The PFS precipitation tended to be higher (lower) than normal for spring (summer) El Nino events during the 1979-2016 period. Our composite analyses reveal that, for spring El Nino events, the sea surface temperature (SST) anomaly in the central-east equatorial Pacific (CEEP) Ocean provided favourable large-scale circulation for abundant PFS precipitation, where the Hadley cell served as a bridge. In the year following an El Nino event, SST anomalies in the CEEP persist from January to June, while for April-May-June (AMJ) positive SST anomalies are seen offshore near China. These anomalies are associated with the AMJ-enhanced convective instability over South China through a weakened Walker circulation and a zonal teleconnection wavetrain pattern at 700 hPa in the northern hemisphere. Meanwhile, a weakened 200 hPa anticyclonic shear was seen over the Indochina Peninsula. There was a southwestward shift of the 500 hPa western Pacific subtropical high, and anomalous 850 hPa southwesterly wind-enhanced water vapour and warm advection toward South China. Therefore, the circulation-induced moisture environment and dynamical conditions both facilitated enhanced PFS precipitation over South China. For summer El Nino events, the moisture environment and dynamical conditions were unfavourable for producing precipitation, which resulted in below-normal PFS precipitation levels. Categorizing El Nino events by the onset time is very important because it provides useful information for predicting PFS precipitation with lead times of two or three seasons.