| 2011年春夏长江中下游旱涝急转的低频环流系统变化 |
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| 引用本文： | 刘佩佩,巩远发,李妍,连帆.2011年春夏长江中下游旱涝急转的低频环流系统变化[J].成都信息工程学院学报,2014,29(5):522-527. |
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| 作者姓名： | 刘佩佩 巩远发 李妍 连帆 |
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| 作者单位： | 成都信息工程学院大气科学学院,高原大气与环境四川省重点实验室,四川成都610225 |
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| 基金项目： | 国家自然科学基金资助项目，公益性行业(气象)科研资助项目 |
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| 摘 要： | 为研究2011年春夏长江中下游地区旱涝急转现象与低频环流的关系,利用国家气象信息中心的753站逐日降水、NCEP/NCAR再分析资料和带通滤波的方法,得到如下结果：（1）2011年5-6月,长江中下游地区存在明显旱涝急转现象,5月的降水较同期偏少40％以上,6月的降水较同期偏多60％。（2）5-6月的旱涝急转前后,长江中下游地区的500hPa的垂直速度变化不仅与降水有很好的关系,而且其低频振荡的强度也显著加强,垂直速度由正（下沉运动）转负（上升运动）的转换时间几乎对应由旱转涝的时间。（3）对旱涝急转过程的500hPa低频变化垂直速度下沉运动最强、下沉运动向上升运动转换、上升运动最强3个位相的低频散度场分析发现,在5月干旱期间,长江中下游地区维持对流层低层（850hPa）辐散、高层（200hPa）辐合的低频环流系统,不利于降水。到6月强降水期,长江中下游地区则迅速转为对流层低层辐合、高层辐散的低频环流系统,有利于降水的发生。这种对流层低层-高层低频环流系统的变化是导致旱涝急转的重要原因之一。
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| 关 键 词： | 气象学 亚洲季风系统 旱涝急转 低频环流系统 垂直速度 |
The Low-frequency Circulation System During the Drought-flood Abrupt Changes Over the Middle-lower Reaches of the Yangtze River in the Spring and Summer 2011 |
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| LIU Pei-pei,GONG Yuan-fa,LI Yan,LIAN Fan.The Low-frequency Circulation System During the Drought-flood Abrupt Changes Over the Middle-lower Reaches of the Yangtze River in the Spring and Summer 2011[J].Journal of Chengdu University of Information Technology,2014,29(5):522-527. |
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| Authors: | LIU Pei-pei GONG Yuan-fa LI Yan LIAN Fan |
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| Institution: | 1.College of Atmospheric Science Center for Plateau Atmospheric and Environment Research, Chengdu University of Information Technology, Chengdu 610225, China) |
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| Abstract: | Study has been made on the relations between the drought-flood abrupt change phenomenon and low frequency circulation happened over the middle-lower reaches of the Yangtze River in the spring and summer 2011,by using the 753 meteorological stations daily precipitation of the National Meteorological Information Center and the NCEP/NCAR reanalysis data.Results show that：（1） in May2011,there＇s 40％ less rainfall occurred than in the same period over the middle-lower reaches of the Yangtze River,but there＇s 60％ more rainfall in June 2011.So the drought-flood abrupt change phenomenon can be obviously seen.（2） Before and after the drought-flood abrupt change,the 500hPa vertical velocity of the middle-lower reaches of the Yangtze River not only has a good relationship with precipitation,but also its amplitude of the low frequency oscillation is intensified obviously.（3） It is analyzed that the low-frequency divergence of the three phases during the strongest sinking speed,sinking speed to rising speed conversion and the strongest rising speed of the 500hPa vertical velocity low-frequency rhythms.Which is found that,before （after） the drought-flood abrupt changes,there is the quickly shift of the low-frequency circulation systems of the 850hPa divergence （convergence） and the 200hPa convergence （divergence） over the middle-lower reaches of the Yangtze River.Therefore,the transition of the low-frequency circulation systems between the lower and upper troposphere is one of the important cause of the drought-flood abrupt changes in spring and summer 2011. |
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| Keywords: | meteorology the Asian monsoon system middle-lower reaches of the Yangtze river drought-flood abrupt changes low-frequency circulation system vertical speed |
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