| 南海夏季风北推时间及相关环流变化特征 |
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| 引用本文： | 李春晖,梁建茵,郑彬,林爱兰,谷德军.南海夏季风北推时间及相关环流变化特征[J].应用气象学报,2007,18(2):202-210. |
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| 作者姓名： | 李春晖 梁建茵 郑彬 林爱兰 谷德军 |
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| 作者单位： | 中国气象局广州热带海洋气象研究所, 广州 510080 |
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| 基金项目： | 科技部社会公益研究项目;广东省自然科学基金;热带海洋气象科研项目 |
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| 摘 要： | 利用1958—2004年NCEP/NCAR逐日再分析资料和我国730站降水资料分析了南海夏季风爆发后影响到华南地区的时间差异及其环流变化特征。结果表明:南海夏季风向北推进影响到华南地区的时间存在明显差异，最早的可以1 d就推进影响到华南地区，最晚的却要42 d，并且这种变化具有明显的年代际变化特征，即20世纪70年末以前，南海夏季风影响到华南地区的时间总体上要偏早，而70年代末以后，南海夏季风影响到华南地区的时间总体上要偏晚；当南海夏季风建立后，若东亚大槽较深，冷空气活动较活跃，索马里越赤道气流形成的西南风、110°~120°E地区越赤道气流形成的偏南风以及副热带高压西侧边缘的偏南风均偏弱，南亚高压和东亚地区急流位置偏南，就会使得南海夏季风影响到华南地区的时间偏晚，反之，则偏早；南海夏季风推进影响到华南地区的时间偏晚（早）年期间，索马里、105°E和130°E越赤道气流输送的水汽通量和西太平洋副热带高压南部的东南气流水汽输送均较弱（强），华南地区前汛期的锋面降水较强（弱）。
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| 关 键 词： | 南海夏季风 推进 华南 环流变化特征 |
| 收稿时间： | 2006-03-20 |
| 修稿时间： | 2006-11-02 |
The Period of South China Sea Summer Monsoon Advanced Northward with the Related Circulation Change Features |
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| Li Chunhui Liang Jianyin Zheng Bin Lin Ailan Gu Dejun.The Period of South China Sea Summer Monsoon Advanced Northward with the Related Circulation Change Features[J].Quarterly Journal of Applied Meteorology,2007,18(2):202-210. |
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| Authors: | Li Chunhui Liang Jianyin Zheng Bin Lin Ailan Gu Dejun |
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| Affiliation: | Institute of Tropical and Marine Meteorology, CMA, Guangzhou 510080 |
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| Abstract: | The Southern China is one of the most rainy areas in the country, which is affected by both the tropical and subtropical monsoon.From April to June, the Southern China experiences the first rainy period, namely the pre rainy season, which is also the first phase that the annual rain belt starts appearing and pushes northward.For the whole Southern China, heavy rain during the target months uses to cause a flood, which accounts for 40%—50% or even more of the whole year precipitation.Because they are concentrated and severe, the rains during the pre rainy season always get more attention and have been studied a lot.But, currently some researches always consider the pre rainy season as a whole.In fact, the pre rainy season can be divided into two phases i, e., the frontal rainfall and the monsoon rainfall.But now, there are not yet any analytical studies on it.The time when the South China Sea summer monsoon breaking out does not mean the commencement of the Southern China summer monsoon precipitation until the South China Sea summer monsoon pushes northward to Southern China, which causes the sec ond peak of the pre rainy season.Therefore, the study can distinguish the frontal rainfall and monsoon rainfall reasonably and get the time when the South China Sea summer monsoon affects the Southern China and the characteristic of the related circulation change, it will be beneficial to providing a new way of thinking for improving precipitation forecasting of the pre rainy season in Southern China.Based on European Center for Medium range Weather Forecast (ECMWF) and NCEP daily reanalyzed dataset from 1958 to 2004 and the surface air temperature/rainfall records from 730 stations in China, the results show that the time exists obvious differences.Also, this variety has obvious inter decadal change characteristic, namely that the time the Southern China summer monsoon affects the Southern China is early before 1970s and late in the late 1970s.When the Southern China summer monsoon breaks out, if the East Asian trough is deeper, the cold air activity is more active, the south west wind from the crossing equatorial currents of Somali and around 110°—120 °E areas and the west part of the subtropical high is weaker, and the position of the South Asia high and the East Asian jet is more southward, it would cause the time to be later, otherwise it would cause the time to be earlier.During the period that the Southern China summer monsoon affected the Southern China later (earlier), the transportation of the moisture from the crossing equatorial currents of Somali and around 105°E and 130°E areas and the southeast part of the west Pacific subtropical high is weaker (stronger), the frontal precipitation of the pre rainy season rainfall in the Southern China is stronger (weaker). |
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| Keywords: | the South China Sea summer monsoon advance the Southern China the characteristic of circulation change |
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