热带气象学报2017，Vol.33Issue(1)：1-10,10.DOI:10.16032/j.issn.1004-4965.2017.01.001
ENSO对中国冬半年降水影响的不对称性及机制分析
IMPACT OF ENSO ON THE PRECIPITATION OVER CHINA IN WINTER HALF YEAR
摘要
Abstract
The impact of ENSO on the precipitation over China in winter half year is investigated by using observed and reanalysis datasets in 1979-2010.The results show that positive precipitation anomalies with statistical significance appear over southern China in El Ni(n)o episodes,which are caused by the enhanced warm and humid southwesterliesalong the East Asian coast in the lower troposphere.The enhanced southwesterlies transport more water vapor to southern China,and the convergence of water vapor over southern China increases the precipitable water and specific humidity in the atmosphere.In La Ni (n)a episodes,no reverse precipitation anomalies with statistical significance appear over southem China.Although atmospheric elements are changed reversely,they are not statistically significant as those in El Ni (n)o periods.The possible physical mechanism of the asymmetric impact of ENSO cycles on the precipitation over southern China is investigated by analyzing the intraseasonal oscillations (ISOs) in El Ni(n)o and La Ni (n)a,respectively,in winter half year.By comparing the characteristics of ISOs in El Ni(n)o and La Ni(n)a,a physical mechanism is proposed to explain the asymmetric responses of the precipitation over China toENSOin winter half year.In El Ni(n)o episodes,over westem North Pacific (WNP) and South China Sea (SCS)the ISOs are inactive and exert little effect on the water vapor transport and convergence,inducing the positive precipitation anomalies with statistical significance over southern China in El Ni(n)o episodes.In La Ni(n)a episodes,however,the ISOs are active,which weaken the interannual variation signals of ENSO over WNP and southern China and lead to the insignificance of the interannual signals related to ENSO.Therefore,the asymmetric responses of precipitation over China to ENSO in winter half yearare possibly caused by the difference of intraseasonal oscillations over WNP and SCS between El Ni(n)o and La Ni(n)a.关键词
气候学/中国降水特征/ENSO/季节内振荡/冬半年Key words
climate/characteristics of precipitation over China/ENSO/intraseasonal oscillation/winter half分类
天文与地球科学引用本文复制引用
李天然,张人禾,温敏..ENSO对中国冬半年降水影响的不对称性及机制分析[J].热带气象学报,2017,33(1):1-10,10.基金项目
国家自然科学基金项目(41221064) （41221064）
公益性行业(气象)科研专项经费项目(GYHY201306004)共同炎助 （气象）
