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中国沙漠 ›› 2014, Vol. 34 ›› Issue (5): 1343-1352.DOI: 10.7522/j.issn.1000-694X.2013.00447

• 天气与气候 • 上一篇    下一篇

1953-2012年中国西北地区东部低层气旋性风场演变特征及成因

赵光平, 马丽   

  1. 南京信息工程大学 大气科学学院, 江苏 南京 210044
  • 收稿日期:2013-09-26 修回日期:2013-12-30 出版日期:2014-09-20 发布日期:2014-09-20
  • 作者简介:赵光平(1962-),男,山东牟平人,正研级高工,主要从事天气预报业务及灾害性天气防灾减灾对策研究。Email:zgp@nuist.edu.cn
  • 基金资助:
    国家自然科学基金项目(41075069,40965008)资助

Characteristics and Causes of Low-level Wind Shear's Evolution over the Eastern Part of Northwest China during 1953-2012

Zhao Guangping, Ma Li   

  1. College of Atmospheric Science, Nanjing University of Information Science & Technology, Nanjing 210044, China
  • Received:2013-09-26 Revised:2013-12-30 Online:2014-09-20 Published:2014-09-20
  • Contact: 马丽(Email:kaixinguoml@126.com)

摘要: 利用1953-2012年NCEP/NCAR全球再分析风场资料,结合同期NCEP全球月平均再分析资料和74项环流特征量资料,通过相关分析、M-K突变检验、小波分析等合成诊断分析方法,研究了近60年中国西北地区东部低层气旋性风切变频次的演变特征,并对其演变的成因进行了初步探讨。结果表明:西北地区东部低层气旋性风切变发生频次在近60年来呈显著的减少趋势,通过了a=0.001的显著性水平检验;风切变频次在1976年出现较明显的由多到少的突变,间接证实近30年来在西北地区东部低层出现风场辐合的次数显著减少,可能产生系统性降水的辐合条件下降;1960-1970年存在3~7年的振荡周期,其中以3年和7年的周期最为显著,基本与西北地区降水周期在时空上较吻合。西北地区东部低层气旋性风场演变的主要原因是大气环流在同一时期发生了较为显著的调整。

关键词: 西北地区, 低层风切变, 大气环流

Abstract: In this paper, the global reanalysis wind data and the mean monthly reanalysis data of NCEP/NCAR in 1953-2012 are used to analyze the characteristics and causes of low-level wind shear's evolution over the east part of Northwest China, with the method of correlation analysis, variation rate analysis, and Mann-Kendall test and wavelet analysis. Results show that the annual low-level cyclonic wind shear frequency decreased significantly in the 60 years, and there was an abrupt change point in 1976. The wind field convergence decreased significantly and the convergence condition which may induce precipitation appeared less in the recent 30 years in the east part of Northwest China. There is 3-7 year oscillation periods in 1960-1970, and the 3 year and 7 year periods were the most remarkable. It basically coincided to the period of the precipitation in Northwestern China in time and space. The main reason of the low-level cyclonic wind field evolution was the significant adjustment of atmospheric circulation in the same period.

Key words: Northwest China, low-level wind shear, atmospheric circulation

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