ENSO对中国南方降水低频变率的可能影响
投稿时间: 2017-01-01  最后修改时间: 2017-01-25  点此下载全文
引用本文:
摘要点击次数: 278
全文下载次数: 
作者单位E-mail
张文君 南京信息工程大学 zhangwj@nuist.edu.cn 
雷徐奔 南京信息工程大学  
耿新 南京信息工程大学  
祁莉 南京信息工程大学  
基金项目:国家自然科学基金项目(面上项目,重点项目,重大项目)
中文摘要:本文利用1979-2012年Hadley中心海表温度、NCEP/NCAR全球再分析资料和中国2474个台站逐日降水资料,分析了不同类型ENSO事件秋冬季和次年春季中国南方地区10-30d降水低频变率的变化特征。结果表明,中国南方地区10-30d降水低频变率对不同类型ENSO事件的响应存在显著的季节差异。EP El Ni駉的冬季和次年春季,低频降水变率显著增强;CP El Ni駉秋冬季低频降水强度呈现相反的异常,秋季低频降水偏弱,而冬季则偏强;La Ni馻事件期间中国南方低频降水变率的变化较小且不稳定。进一步分析发现,ENSO对南方地区10-30d低频降水变率的影响与西北太平洋地区季节平均大气环流背景场对ENSO的响应密切相关。相比起正常年份,EP El Ni駉冬春季菲律宾反气旋性异常环流的强度较强且范围较大,其西侧的异常西南风向中国南方地区输送了大量水汽,从而有利于低频降水的增强;CP El Ni駉年秋季西北太平洋表现为气旋性环流异常,抑制热带水汽向东亚大陆输送,而冬季却产生了与EP El Ni駉年类似的反气旋环流,只是强度有所减弱,因此其低频降水强度在秋冬季呈相反异常。La Ni馻年菲律宾附近呈现气旋性环流异常,但强度较弱,因而我国南方地区低频降水变率的响应也较弱。
中文关键词:中国南方地区, 10-30d低频降水变率, ENSO
 
Possible impact of ENSO on the intra-seasonal variability of precipitation over southern China
Abstract:Features of intra-seasonal (10-30d) variability of precipitation over southern China during autumn, winter and the following spring of different types of ENSO are analyzed based on the Hadley Centre sea surface temperature (SST), the National Centers for Environmental Prediction (NCEP)/the National Center for Atmospheric Research (NCAR) atmospheric circulation data and China daily rainfall station data. Results show that impacts of different ENSO types on the intra-seasonal (10-30d) precipitation variability over southern China vary with different seasons. During the winter and following spring of EP El Ni駉 events, the 10-30d precipitation variability over southern China is significantly enhanced. Intra-seasonal precipitation variance is weakened during the CP El Ni駉 autumn while strengthened during the CP El Ni駉 winter, showing inverse features. The impacts of La Ni馻 events on the 10-30d precipitation variability are relatively small and unstable. Further analyses show that the impact on the 10-30d precipitation variability is closely related to the responses of seasonal atmospheric circulation anomalies over the western North Pacific associated with ENSO events. Compared with the normal years, a strong anticyclonic circulation anomaly occurs over the Philippines during the EP El Ni駉 years. The anomalous southerly winds in the west side of the anticyclone transport much more water vapor northward to southern China, which favors strengthened 10-30d rainfall variability. However, an anomalous cyclonic circulation occurs in the western North Pacific during CP El Ni駉 autumn, which suppressed the tropical water vapor transporting northward to the East Asian continent. During CP El Ni駉 winters, an anomalous anticyclone appears over the western North Pacific although its intensity is weak, which accounts for the inverse low frequency rainfall responses in autumn and winter. When La Ni馻 occurs, the cyclonic circulation over Philippine is weak, which results in the relatively weaker responses of the 10-30d precipitation variability over southern China.
keywords:southern China, 10-30d intra-seasonal precipitation variability, ENSO
查看全文  查看/发表评论  下载PDF阅读器