摘要
根据中国气象局国家气候中心提供的1951~2005年中国160个站月降水量资料，用扩展的EOF（EE—OF）分析、小波变换、相关分析和合成分析方法，研究了中国东部夏季风雨带季节性南北变动的主导模态和时空变化的特征，分析了各模态的气候特点及其与西太平洋副热带高压季节内变异的关系。研究表明，我国夏季雨带季节性进退活动不仅是多态的而且是多时间尺度的现象。主导模态主要有六种，为了对各模态雨带推进过程的不同特点有个概要的认识，分别称之为：梅涝型、伏旱型、梅旱型、南涝北旱型、常态型和南旱北涝型。这六种模态基本上反映了我国东部夏季雨带季节性移动异常的各种情况。在时间尺度上，各模态普遍存在准两年、3～5年和准8年的年际变化，以及准10年、准15年、准24年和准30年的年代际变化。但各模态的优势周期存在明显差别，尤其是年代际变化。分析还表明，西太平洋副热带高压的季节性变异是影响我国东部夏季雨带季节内时空变化最直接和最主要的原因。基本上，不同型式的副高变异对应有不同的雨带季节内变化模态和天气气候特征。这些研究结果可为我们进一步探讨中国夏季雨带季节内变异各模态形成的物理过程和成因提供基础。
The dominant modes and temporal and spatial characteristics of the intraseasonal variability of summer monsoon rain belt are studied by using extended empirical orthogonal function （EEOF）, wavelet transform, correlation and composite methods with 160-station monthly mean precipitation data （1951 - 2005） offered by the National Climate Centre of China Meteorological Administration. The climatic characteristics of dominant modes and their relationships with the western Pacific subtropical high intraseasonal variability are discussed. The results show that the intraseasonal variability of summer rain belt is not only multi-patterns, but multi-time scales. There are six dominant modes of the intraseasonal variability of summer rain belt. In order to give a brief features of seasonal northward movement of summer rain belt for different dominant modes, the six dominant modes are named respectively： flood pattern during Meiyu period, drought pattern in dog days, drought pattern during Meiyu period, south flood-ing/north drought pattern, normal pattern and south drought/north flooding pattern. The intraseasonal variation characteristics are as follows.
Mode-1 ： The rain belt is located in the north of southern China in June. But it is more southward than normal in July and August, which leads to the main rain belt persisting longer than normal over the Yangtze River and its neighborhood and more floods over there.
Mode-2. The rain belt stays south of the Yangtze River in June, jumps over the Yangtze River, comes to the Yellow River and its north in July and continues to stay there in August. The main rain belt stays more shortly than normal over the Yangtze River during the Meiyu period and stays north of China in mid-summer, which leads to droughts over the Yangtze River and Huaihe River valleys in mid-summer while floods over the Yellow River and its north. Mode-3： The rain belt is more northward than normal in June, and the rainfall is less in the north of southern China. And the main rain belt is
出处
《大气科学》
CSCD
北大核心
2007年第6期1212-1222,共11页
Chinese Journal of Atmospheric Sciences
基金
国家重点基础研究发展规划项目2004CB418303
中国科学院知识创新重要方向性项目KZCX3-SW-226
国家自然科学基金资助项目40523001
关键词
夏季风降水
主要雨带
季节内变异
模态
summer monsoon rainfall, main rain belt, intraseasonal variation, mode
