| 夏季长江淮河流域异常降水事件环流差异及机理研究 |
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| 引用本文： | 张庆云,郭恒.夏季长江淮河流域异常降水事件环流差异及机理研究[J].大气科学,2014,38(4):656-669. |
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| 作者姓名： | 张庆云 郭恒 |
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| 作者单位： | 1.中国科学院大气物理研究所国际气候与环境研究中心, 北京 100029;中国科学院大气物理研究所大气科学和地球流体力学数值模拟国家重点实验室, 北京 100029 |
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| 基金项目： | 国家自然科学基金项目41375055，全球变化研究国家重大科学研究计划项目2012CB957803，国家重点基础研究发展计划项目2013CB430201 |
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| 摘 要： | 长江、淮河同处东亚中纬度，天气过程的大尺度环流背景相似，大量相关研究基本是把江淮流域天气气候事件作为一个整体研究，然而对长江、淮河流域夏季降水的时空变化进行分析发现，长江、淮河流域夏季异常降水事件有各自不同的年际、年代际变化特征，但环流差异及成因并不十分清楚。本文根据中国台站降水资料及NCEP/NCAR再分析资料，利用物理量诊断和现代统计学等方法，重点分析长江、淮河流域梅雨期降水异常事件发生时南北半球大气环流内部动力过程的差异及成因。研究指出:长江（淮河）流域梅雨期降水异常偏多年500 hPa位势高度场亚洲中高纬度环流呈现为南北向（东西向）的波列与东亚中高纬鄂霍茨克海阻塞频次增多（减少）以及200 hPa高度场上东亚副热带高空西风急流强度加强（减弱）、稳定（移动）有关；长江（淮河）流域梅雨期降水异常偏多年主要水汽来源与南半球澳大利亚高压、马斯克林高压位置偏东（西）造成西太平洋150°E～180°（阿拉伯海50°E～60°E）地区越赤道气流加强有关。长江（淮河）流域梅雨期异常降水事件大气环流内部动力过程最显著的差异表现为:东亚副热带高空西风急流加强（减弱）以及南半球澳大利亚高压、马斯克林高压位置偏东（西）。
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| 关 键 词： | 长江(淮河)流域降水 东亚高空西风急流 南半球环流 越赤道气流 |
| 收稿时间： | 8/8/2013 12:00:00 AM |
| 修稿时间： | 2014/2/27 0:00:00 |
Circulation Differences in Anomalous Rainfall over the Yangtze River and Huaihe River Valleys in Summer |
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| ZHANG Qingyun and GUO Heng.Circulation Differences in Anomalous Rainfall over the Yangtze River and Huaihe River Valleys in Summer[J].Chinese Journal of Atmospheric Sciences,2014,38(4):656-669. |
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| Authors: | ZHANG Qingyun and GUO Heng |
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| Institution: | International Center for Climate and Environment Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029;State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029;International Center for Climate and Environment Sciences, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029;University of Chinese Academy of Sciences, Beijing 100049 |
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| Abstract: | Both the Yangtze River and the Huaihe River lie in mid-latitudes in East Asia, and so the large-scale circulation and climatic background of weather events in the Yangtze River valley and the Huaihe River valley are similar. However, there are different interannual variations between anomalous rainfall events in the Yangtze River valley and in the Huaihe River valley in summer. This study focuses on differences in circulation in middle to high latitudes in Asia and middle to low latitudes in the southern hemisphere, and the associated mechanisms. Both physical and statistical methods were used in this study. We looked at the differences in Asian circulation for anomalous rainfall events in the Yangtze River basin and the Huaihe River valley in summer. East Asian subtropical westerly winds at 200 hPa strengthened (weakened) and a longitudinal (zonal) pattern with anomalous geopotential height at 500 hPa occurred in middle to high latitudes over East Asia. Meanwhile, the locations of both the Australian anticyclone and the Mascarene anticyclone shifted further east (west), respectively, than normal, the cross-equatorial flow strengthened in the areas 150°E to 180° and weakened in the areas 50°E to 60°E (weakened in the areas 150°E to 180° and strengthened in the areas 50°E to 60°E), and anomalous rainfall in summer occurred in the Yangtze River valley (the Huaihe River valley). Thus, the intensity of East Asian subtropical westerly winds as well as the locations of both the Australian anticyclone and the Mascarene anticyclone played an important role in the occurrence of anomalous rainfall events in the Yangtze River valley and the Huaihe River valley in summer. |
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| Keywords: | Anomalous rainfall Yangtze River Huaihe River East Asian subtropical westerly winds Southern Hemisphere circulation Cross-equatorial flow |
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