| 500hPa广义位温场与我国西北地区夏季降水的关系 |
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| 引用本文： | 敖婷,;李跃清.500hPa广义位温场与我国西北地区夏季降水的关系[J].甘肃气象,2014(2):175-183. |
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| 作者姓名： | 敖婷 ;李跃清 |
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| 作者单位： | [1]中国气象科学研究院,北京100081; [2]中国气象局成都高原气象研究所,四川成都610072 |
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| 基金项目： | 国家重点基础研究发展计划项目（2012CB417202）、国家公益性行业（气象）科研专项经费项目（GYHY201006053）及高原气象观测与应用创新团队专项共同资助 |
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| 摘 要： | 利用1958~2012年JRA55月平均再分析资料和我国西北地区33站降水资料,通过EOF、相关、合成、SVD等统计方法,分析了500 hPa广义位温场与我国西北地区夏季降水的关系。结果表明:夏季500 hPa关键区(40°E~80°E,30°N~60°N)广义位温场与我国西北地区降水关系最为密切,当里海、咸海、贝加尔湖以北地区对流层中层偏暖湿,中亚南部偏冷干时,我国西北地区西部降水偏多,而东部降水偏少。尤其是在新疆南部及甘肃北部降水偏多更为显著,而甘肃南部降水偏少则最为明显;反之亦然。前期2月500 hPa广义位温场自赤道阿拉伯海沿南亚印度北部、中国西北至北亚,呈西南东北向的"+﹣﹢﹣"分布时,随后夏季西北地区降水西部多、东部少。并且,夏季关键区对流层中层广义位温场的异常变化,对应着不同的大气环流场异常,而这种环流形势则进一步影响我国西北地区东西部的降水异常。
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| 关 键 词： | 广义位温 西北地区 夏季降水 |
Relationship Between 500 hPa Generalized Potential Temperature and Summer Precipitation in Northwest China |
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| Institution: | AO Ting , LI Yueqing ( 1. Chinese Academy of Meteorological Sciences, Beijing 100081, China ; 2. Institute of Plateau MeteorologT , CMA, Chengdu 610072, China ) |
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| Abstract: | Based on the JRA55 monthly averaged reanalysis data during1958 -2012 and monthly precipitation data from 33 stations inNorthwest China,the relationships between 500 hPa generalized potential temperature and summer precipitation over there were dis cussed by using the EOF,correlation,composite and SVD technique. Results show that the 500 hPa generalized potential temperatureover the key areas （40°E -80°E,30°N - 60°N）in summer was closely related with the contemporaneous precipitation in NorthwestChina. When the north areas of Caspian Sea,Aral Sea and Lake Baikal were warmer and wetter,and Southern Central Asia was colderand drier,the precipitation increased in western region and decreased in eastern region of Northwest China,especially in southern Xin jiang and northern Gansu the increase of precipitation was the most significant,while in southern Gansu the decrease of precipitationwas the most obvious,and vice versa. When the 500 hPa generalized potential temperature in February presented “＋-＋-”distri bution from southwest to northeast along the Arabian sea,northern India,northwest China to north Asia,the following summer precipi tation in western region increased and decreased in eastern region of Northwest China. Furthermore,anomalous variations of the gener alized potential temperature in the middle troposphere over the key areas corresponded to different atmospheric circulation anomalies,which can further affect the precipitation anomalies in western and eastern region of Northwest China. |
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| Keywords: | generalized potential temperature Northwest China summer precipitation |
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