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干旱区地理 ›› 2015, Vol. 38 ›› Issue (2): 207-214.

• 气候与水文 •    下一篇

河西走廊东部极端降水的时空分布及影响因子分析

钱莉,杨永龙,张宇林,腾杰,刘菊菊   

  1. (甘肃省武威市气象局, 甘肃    武威    733000)
  • 收稿日期:2014-03-18 修回日期:2014-05-02 出版日期:2015-03-25
  • 作者简介:钱莉(1963-),女,浙江金华人,高级工程师,主要从事天气气候研究工作. Email:wwqxjql@163.com
  • 基金资助:

    甘肃省气象局2012年科研项目“武威市强对流天气预报指标研究”

Temporal and spatial distribution and influence factors of extreme precipitation in eastern Hexi Corridor

QIAN  Li,YANG  Yong-long,ZHANG  Yu-lin,TENG  Jie,LIU  Ju-ju   

  1. (Wuwei Meteorological Bureau,Wuwei  733000,Gansu,China)
  • Received:2014-03-18 Revised:2014-05-02 Online:2015-03-25

摘要: 利用线性回归分析、Mann-Kendall检验法和和小波分析法,统计分析了河西走廊东部1961-2012年近52 a来暴雨日数的变化规律。结果表明:河西走廊东部年平均暴雨日数为1.2 d·a-1,多为局地暴雨,暴雨日数时空分布差异大,从南向北、从东向西暴雨日数迅速递减,暴雨最多的地方出现在祁连山北坡迎风坡的古浪县。然而,年暴雨日数变化总体呈上升趋势,其线性倾向率为0.24次·(10 a)-1,年暴雨日数最多年代出现在21世纪00年代,出现15场次;最少的年代出现在20世纪80年代,仅为6场次;区域性暴雨出现最多年代、最少年代与区域性暴雨强度呈相反态势。暴雨日数受季风变化影响显著,出现时段集中在6~8月,占全年暴雨日数的90.3%。其中8月暴雨日数最多,占总次数的48.4%;一日中暴雨主要出现在白天。采用Mann-Kendall检验法进行检验,河西走廊东部年暴雨日数增加从1963年开始,1985-2012年为显著增加,气候变暖使区域内极端降水出现次数增多。小波分析发现暴雨日数存在9 a和6 a周期。区域内年降水量与暴雨日的变化趋势相同,说明区域内极端降水日数增多导致了年降水量的增加。利用1983-2012年近32 a的NCEP再分析资料,将暴雨出现的高空环流形势归纳为副高西部西南气流型、河套阻塞高压型,大量级暴雨产生在高空河套阻塞高压型中;根据暴雨产生的物理机制,归纳总结出河西走廊东部暴雨产生的物理要素阈值。

关键词: 暴雨, 时空分布, 环流特征, 物理量阈值, 河西走廊东部

Abstract: This paper mainly analyses the pattern of the variation of rainstorm days at east part of the Hexi Corridor,Gansu Province,China from 1961 to 2012 by using linear regression analysis,Mann-Kendall method,and wavelet analysis method. The results show that the average number of rainstorm days was 1.2 d·a-1 at the eastern part of the Hexi Corridor,and it mainly was local rainstorm within the region. The temporal and spatial distribution of rainstorm days vary considerably: the number decreases rapidly southward and eastward. The most intense rainstorm mainly occurs at the Gulang County located in the windward slope of the Qilian Mountains. The number of rainstorm days has an annually increasing trend in general,and the liner tendency rate is 0.24 d·(10 a)-1. The most one occurs in the 2000s century with 15 days of rainstorm,while the least one occurs in the 1980s with only 6 days. The sub-regional rainstorm has the opposite trend with the regional rainstorm in the period of the most one and the least one. The variation of monsoon has a significant impact on the number of rainstorm days,which results in rainstorms frequently occur in June to August. The number of rainstorm days within these months account for 90.3% of the whole year rainstorm days. Among which August has the largest number of rainstorm days accounting for 48.8%. The rainstorm mainly occurs in the daytime. Using Mann-Kendall method,the number of rainstorm days at the east of Hexi Corridor has been increasing since 1963 and from 1985 to 2013,the number increases significantly. Warmer weather may be one of the causes for the increasing extreme precipitation frequency. Wavelet analysis method shows that the number of rainstorm days has a nine-year and a six-year period. The regi- onal yearly precipitation has a similar varying trend to the number of rainstorm days,which indicates that the inc- reasing days of extreme raining may cause the yearly precipitation to increase as well. Based on the NCEP reanalysis data from 1983 to 2012 nearly 32 years,the upper air circulation of rainstorm has been summarized as the west-southwest flow type of the western subtropical high and the blocking high type in Hetao area,while a large class rainstorm happened in the type of the blocking high in Hetao. Threshold of physical elements of occurrence of rainstorm has also been calculated by analyzing the physical mechanism of rainstorm happened in Hexi Corridor.

Key words: rainstorm, temporal and spatial distribution, circulation characteristics, physical quantity threshold, eastern Hexi Corridor

中图分类号: 

  • P426.61