| 西北地区中东部秋季连阴雨天气过程与环流背景诊断分析 |
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| 引用本文： | 白晓平,成孝平,张英华.西北地区中东部秋季连阴雨天气过程与环流背景诊断分析[J].安徽农业科学,2014(10):3027-3029,3035. |
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| 作者姓名： | 白晓平 成孝平 张英华 |
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| 作者单位： | [1]兰州大学大气科学学院,甘肃兰州730000 [2]中国人民解放军94195部队,甘肃定西730500 |
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| 摘 要： | 利用1956～2003年的NCEP资料(2.5°×2.5°)和西北地区5个气象站的逐日降水资料,对出现在我国西北地区中东部(甘肃河东和宁夏南部)的秋季连阴雨天气过程进行了统计分析。结果表明,连阴雨次数在20世纪总体上呈下降趋势;连阴雨的环流形势,在高纬为一槽一脊或二槽一脊,中纬度短波活动较多,青藏高原为一槽区,西北地区中东部受西南暖湿气流的控制且为高能区,短波活动带来的冷空气与西南暖湿气流在西北地区中东部不断交馁,造成降水过程;对流层中部500 hPa欧亚环流形势相对稳定,乌拉尔山的长波脊和中亚低槽维持,该区域的偏南气流为该区输送了大量的水汽,从而形成了西北地区中东部持续的连阴雨天气;当西风带中纬度新疆高压脊建立,副热带高压东移南退时,西北地区中东部的连阴雨天气过程结束。
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| 关 键 词： | 西北地区 连阴雨 环流形势 物理量 诊断分析 |
Diagnostic Analysis of Weather and Circulation Background of Autumn Steady Raining in Central and Eastern Portions of Northwest Region of China |
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| Institution: | BAI Xiao-ping et al ( College of Atmospheric Sciences of Lanzhou University, Lanzhou, Gansu 730000) |
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| Abstract: | With the daily precipitation data of NCEP data（2.5°× 2.5°） and 5 meteorological stations in northwest during 1956 -2003, the climatic feature of the steady raining which appears in central and eastern part（ east of Gansu and south of Ningxia） of northwest region of Chi- na is statistical analyzed, and it shows the steady raining time views the downward trend in the 20th century, the zonal circulation of steady rai- ning is a trough a ridge or two trough a ridge at high latitude, more short-wave activity at mid-latitude, a trough at the Tibetan Plateau. The central and eastern portions of northwest region of China is controlled by southwest warm wet airflow and in the area of high potential, the cold air by short-wave activity and the warm air are continuous intersected and result the steady raining. The relatively stable zonal circulation at 500 hPa is kept, and the southerly airflow transports a lot of vapor, thus leading the steady raining at the central and eastern portions of north- west region of China; when a mid-latitude Xinjiang high ridge is established and the subtropical high moves eastward and retreats toward the south, the steady raining comes to the end. |
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| Keywords: | Northwest China Steady raining Atmosphere circulation Physics Diagnostic analysis |
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