吴萍,丁一汇,柳艳菊. 2017. El Nino事件对中国夏季水汽输送和降水分布影响的新研究[J]. 气象学报, ():-, doi:10.11676/qxxb2017.033
El Nino事件对中国夏季水汽输送和降水分布影响的新研究
A new study of the impacts of El Nino events on the summer water vapor transport and rainfall in China
投稿时间:2016-10-24  最后修改时间:2016-12-28
DOI:10.11676/qxxb2017.033
中文关键词:  东部型El Nino,中部型El Nino,水汽输送,降水,遥相关型
英文关键词:Eastern Pacific (EP) El Nino, Central Pacific (CP) El Nino, Water vapor transport, Rainfall, Teleconnection
基金项目:国家重点基础研究发展(973)计划(2013CB430202)、公益性行业(气象)科研专项(GYHY201406001和20140618)、国家自然科学基金资助项目(41401056和41275095)、江苏省普通高校研究生科研创新计划项目(KYLX15_0858)
作者单位E-mail
吴萍 1、中国气象科学研究院 2、南京信息工程大学大气科学学院 3、国家气候中心 nj_wp@126.com 
丁一汇 国家气候中心 dingyh@cma.gov.cn 
柳艳菊 国家气候中心 liuyanj@cma.gov.cn 
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中文摘要:
      本文基于1961?2016年我国地面台站降水观测资料和多种再分析资料,分析了东部型和中部型两类El Nino事件对中国夏季水汽输送和降水的不同影响。结果表明:(1)El Nino事件对中国夏季降水的影响在发生当年和次年有明显的不同,主要影响是在其发生的次年,我国大部分地区的夏季降水明显偏多。(2)东部型El Nino事件当年夏季,西太副高偏东偏弱,水汽输送条件较弱,不利于全国大范围降水的发生;中部型事件当年夏季,低纬印度洋和西太平洋蒸发异常偏强,来自阿拉伯海、孟加拉湾和西北太平洋向华南地区的水汽输送和净水汽收支增加,有利于华南地区降水的异常增多。(3)东部型El Nino事件次年夏季,副热带太平洋蒸发异常偏强,西太副高西伸,由于东亚—太平洋(EAP)遥相关型的建立,副高西侧的强西南气流将来自太平洋蒸发的大量水汽持续输送到我国中东部地区。另外在EAP遥相关型影响下中高纬地区建立了亚洲双阻型环流,其间的低槽冷涡与上游阻高之间的强偏北气流有利于北冰洋的水汽持续输送到西北和华北北部地区,全国大部分地区净水汽收支均增加,中国北方和南方地区的降水都产生了明显的同步性增多响应,形成了南北两条异常雨带。中部型事件次年夏季,西太副高较常年偏西且偏北,来自太平洋蒸发的大量水汽输送到江淮地区,使其净水汽收支增加和降水偏多。因此,El Nino事件的发生不仅对长江流域和淮河流域等南方地区的降水有重要影响,对华北、东北和西北地区的降水异常也有相当的作用。
英文摘要:
      Based on the observation precipitation data and multiple reanalysis datasets from 1961 to 2016, the different impacts of eastern Pacific (EP) El Nino and central Pacific (CP) El Nino events on China summer moisture transport and rainfall has been investigated. Results suggest that: (1) the impacts of El Nino events on China summer rainfall are significantly different in the developing summer and decaying summer. The main impacts occur in the decaying summer that the obvious rainfall signals are found in most areas. (2) in the developing summer of EP El Nino events, the western North Pacific (WNP) subtropical high (SH) tends to retreat eastward and be weakened. The weak moisture transport conditions are not conductive to the occurrence of rainfall in most areas. In the developing summer of CP El Nino events, the western Pacific Ocean and low latitude of the Indian Ocean evaporation becomes stronger. Plentiful moisture originating from Arabian Sea, Bay of Bengal and the western Pacific Ocean is transported into South China and the net moisture income increase, tending to induce positive rainfall anomalies in South China. (3) in the decaying summer, extra tropic pacific evaporation increased significantly. The westward WNPSH and the establishment of East Asia/ Pacific (EAP) teleconnection benefit for the southwesterly winds over the western side of the WNPSH carrying abundant water vapor from the Pacific to the central-eastern China. Meanwhile, the double-blocking set up in Eurasia high-mid latitudes and the northerly air between its low trough and its upstream blocking high tends to carry more water vapor from the Arctic Ocean to Northwest China and the north part of North China. The positive net moisture income anomalies are found in most areas in China, providing favorable moisture conditions for the rainfall. Two rain belts are formed in the south and north of China. In the CP El Nino decaying summer, the WNPSH tends to extend westward and northward, contributing to transport of the water vapor originating from the strong Pacific evaporation into Jianghuai region and causing the increase in the net moisture income in Jianghuai region. Hence, El Nino events not only influence the rainfall anomalies in Yangtze River valley and Huai River valley, but also influence the rainfall anomalies in North China, Northeast China and Northwest China.
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