| 近50年长江中下游春季和梅雨期降水变化特征 |
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| 引用本文： | 邓汗青,罗勇.近50年长江中下游春季和梅雨期降水变化特征[J].应用气象学报,2013,24(1):23-31. |
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| 作者姓名： | 邓汗青 罗勇 |
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| 作者单位： | 1.南京信息工程大学气象灾害省部共建教育部重点实验室，南京 210044 |
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| 基金项目： | “973”项目（2010CB428401），江苏省普通高校研究生科研创新计划项目（CXLX12_0505） |
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| 摘 要： | 利用1961—2009年长江中下游地区52个气象站逐日降水资料，研究了该地区春季降水与梅雨期降水的连续变化特征，划分了连续旱、连续涝、先旱后涝和先涝后旱4类连续性事件，并探讨其成因。结果表明:长江中下游地区春季降水量年际和年代际变化较为显著，其中连续旱和连续涝事件发生较多。前冬Ni?o3区的海温与春季和梅雨期降水量相关性超过0.05显著性水平，前冬青藏高原积雪深度与6月西太平洋季风指数与梅雨期降水量相关性均达到0.05显著性水平。当春季水汽丰富，同时春季与6月副热带高压中心位置持续偏西可能导致春季和梅雨期降水持续偏多；春季水汽丰富，但春季至6月副热带高压中心位置由偏西向偏东转变，可能造成先涝后旱；春季水汽偏少，且春季与6月副热带高压中心位置持续异常偏东，易造成持续干旱。2011年水汽突变可能是导致旱涝急转的直接原因，前冬的La Ni?a事件不利于春季降水而6月副热带高压位置异常西伸, 则容易引发旱涝急转。
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| 关 键 词： | 长江中下游 春季降水 梅雨 |
| 收稿时间： | 2012-04-20 |
Continuous Spring and Meiyu Rainfall in the Mid lower Reaches of the Yangtze During the Past 50 Years |
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| Deng Hanqing and Luo Yong.Continuous Spring and Meiyu Rainfall in the Mid lower Reaches of the Yangtze During the Past 50 Years[J].Quarterly Journal of Applied Meteorology,2013,24(1):23-31. |
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| Authors: | Deng Hanqing and Luo Yong |
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| Affiliation: | 1.Key Laboratory of Meteorological Disater of Ministry of Education, Nanjing University of Information Science & Technology, Nanjing 2100442.Center for Earth System Science, Tsinghua University, Beijing 100084 |
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| Abstract: | Using the daily precipitation data from 52 meteorological stations in the mid-lower reaches of the Yangtze and NCEP/NCAR reanalysis data from 1961 to 2009, the characteristics of spring and Meiyu precipitation are analyzed. It shows that spring precipitation takes on significant inter-annual and inter-decadal variations while Meiyu precipitation doesn't. Based on the annual spring and Meiyu precipitation characteristics, it is divided into four classes: Flood-flood, flood-drought, drought-drought and drought-flood. Generally, drought-drought and flood-flood events take place frequently. The variation of circulation features affects the precipitation anomaly too. The mechanism of different type is also discussed, finding the correlation coefficient between previous winter Ni?o3 index and spring, Meiyu precipitation to be 0.42 and 0.30, which reach 0.01 and 0.05 levels, respectively. The previous winter snow of Tibetan Plateau and western Pacific summer monsoon index are shown both significantly correlated with Meiyu precipitation. The abundant water vapor is carried by the anomalous southerly from the South China Sea and the western Pacific, the western Pacific subtropical anticyclone strengthens, and its position leans westward in June. That would make a successive flood event. When water vapor over the reaches is abundant but insufficient in source region, position of the western Pacific subtropical anticyclone appears from west to east anomaly in spring and Meiyu periods, and that would cause the flood-drought events. When water vapor is insufficient in both areas, drought event occurs. In 2011, a sudden turn of drought and flood takes place in the mid-lower reaches of the Yangtze, leading to big economic losses of agriculture. The factors which may cause the sudden turn of drought and flood events are analyzed. The sea surface temperature anomaly of the equatorial eastern Pacific happens in precious winter and less water vapor cause spring drought, and with Meiyu occuring, the western Pacific subtropical anticyclone moving westward and precipitation increasing greatly. On the basis of preliminary analysis of related impact factors, numerical experiments are needed to evaluate the result further. |
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| Keywords: | the mid lower reaches of the Yangtze spring precipitation Meiyu |
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