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500 hPa 广义位温场与我国西北地区夏季降水的关系

敖婷1,2李跃清2   

  1. 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
  • 出版日期:2014-04-18 发布日期:2014-04-18
  • 作者简介:敖婷(1989 - ),女,重庆人,硕士研究生,主要从事高原气候研究. E - mail:berylat@163. com
  • 基金资助:

    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

Relationship Between 500 hPa Generalized Potential Temperature and Summer Precipitation in Northwest China

AO Ting1,2LI Yueqing2   

  1. 1. Chinese Academy of Meteorological Sciences,Beijing 100081,China;
    2. Institute of Plateau Meteorology,CMA,Chengdu 610072,China
  • Online:2014-04-18 Published:2014-04-18

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。

关键词: 广义位温, 西北地区, 夏季降水

Abstract:

Based on the JRA55 monthly averaged reanalysis data during1958 -2012 and monthly precipitation data from 33 stations in
Northwest 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 temperature
over the key areas (40°E -80°E,30°N - 60°N) in summer was closely related with the contemporaneous precipitation in Northwest
China. When the north areas of Caspian Sea,Aral Sea and Lake Baikal were warmer and wetter,and Southern Central Asia was colder
and 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 precipitation
was 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.

Key words: generalized potential temperature, Northwest China, summer precipitation

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