| 江淮流域夏季严重旱涝与大气季节内振荡 |
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| 作者姓名： | YANG Hui LI Chongyin |
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| 作者单位： | LASG，Institute of Atmospheric Physics，Chinese Academy of Sciences，Beijing 100029，LASG，Institute of Atmospheric Physics，Chinese Academy of Sciences，Beijing 100029 |
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| 基金项目： | 国家重点基础研究发展计划(973计划)，中国科学院资助项目，国家重点实验室基金 |
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| 摘 要： | 利用NCEP/NCAR的再分析资料和中国气象局国家气象中心提供的中国台站降水资料,分析研究了江淮流域大范围严重旱涝的20-70天大气季节内振荡(ISO)特征。结果表明,对应江淮流域严重涝年,200hPa青藏高原北部存在ISO气旋性环流,青藏高原南部存在ISO反气旋性环流;大气ISO流型在对流层中低层850hPa主要是我国长江以南、南海和西太平洋地区为大气ISO反气旋性环流,我国长江以北到日本地区的大气ISO气旋性环流,我国江淮流域位于这两个ISO涡旋西侧偏南气流和偏北气流的交汇处;旱年反之。利用向量经验正交展开方法得到,上述大气ISO环流型分别是旱涝年大气ISO流型的第一模态,并且涝年大气ISO流型的振幅强,旱年振幅弱。进一步分析揭示,严重洪涝(干旱)年分别对应对流层中上层江淮流域及其以北的中高纬度地区有强(弱)的大气ISO活动。中高纬度地区的大气ISO在严重洪涝年向南传播,与低纬度向北传播的大气ISO在江淮流域汇合;而在严重干旱年,虽然大气ISO可向北传播,但向南的传播却很不明显。
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| 关 键 词： | 江淮流域夏季严重旱涝 季节内振荡 大气ISO环流型 |
The Relation between Atmospheric Intraseasonal Oscillation and Summer Severe Flood and Drought in the Changjiang-Huaihe River Basin |
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| YANG Hui,LI Chongyin.The Relation between Atmospheric Intraseasonal Oscillation and Summer Severe Flood and Drought in the Changjiang-Huaihe River Basin[J].Advances in Atmospheric Sciences,2003,20(4):540-553. |
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| Authors: | YANG Hui and LI Chongyin |
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| Institution: | LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029,LASG, Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029 |
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| Abstract: | The intraseasonal oscillation (ISO) is studied during the severe flood and drought years of theChangjiang-Huaihe River Basin with the NCEP/NCAR reanalysis data and the precipitation data inChina. The results show that the upper-level (200 hPa) ISO pattern for severe flood (drought) is charac-terized by an anticyclonic (cyclonic) circulation over the southern Tibetan Plateau and a cyclonic (anti-cyclonic) circulation over the northern Tibetan Plateau. The lower-level (850 hPa) ISO pattern is char-acterized by an anticyclonic (cyclonic) circulation over the area south of the Changjiang River, the SouthChina Sea, and the Western Pacific, and a cyclonic (anticyclonic) circulation from the area north of theChangjiang River to Japan. These low-level ISO circulation patterns are the first modes of the ISO windfield according to the vector EOF expansion with stronger amplitude of the EOF1 time coefficient in se-vere flood years than in severe drought years. The analyses also reveal that at 500 hPa and 200 hPa,the atmospheric ISO activity over the Changjiang-Huaihe River basin, North China, and the middle-highlatitudes north of China is stronger for severe flood than for severe drought. The ISO meridional windover the middle-high latitude regions can propagate southwards and meet with the northward propagatingISO meridional wind from lower latitude regions over the Changjiang-Huaihe River Basin during severeflood years, but not during severe drought years. |
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| Keywords: | summer severe flood and drought in the Changjiang-Huaihe River Basin intraseasonal oscillation ISO circulation pattern |
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