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西南地区云量变化特征

李慧晶刘建西刘东升王维佳林丹   

  1. 四川省人工影响天气办公室,四川 成都 610072
  • 出版日期:2014-04-18 发布日期:2014-04-18
  • 作者简介:李慧晶(1984 - ),女,青海人,硕士,助理工程师,主要从事人工影响天气研究工作. E - mail:lihuijing -1984@163. com
  • 基金资助:

    西南区域气象中心 2011 年区域重大科研业务项目“西南地区空中云水资源评估和开发利用研究”(西南区域气 2011 -02)和四川地区雾特征及人工影响潜力研究(川气课题 2013 - 青年 -12))共同资助

Variation Characteristics of Cloud Cover over Southwestern China

LI HuijingLIU JianxiLIU DongshengWANG WeijiaLIN Dan   

  1. Weather Modification Office of Sichuan Province,Chengdu 610072,China
  • Online:2014-04-18 Published:2014-04-18

摘要:

利用西南地区(云南、贵州、四川、重庆)记录较为完整的 73 个测站 1956 ~2005 年月平均云量资料,采用经验正交函数分析和 Mann - Kendall 突变检验方法,研究分析了西南地区云量的时空分布特征。结果表明:就全年而言,整个西南地区总云量的变化趋势一致,且存在着明显的年际变化特征,1990 年代以后全年总云量表现出减少趋势;此外,总云量的分布在一定程度上受地形和区域气候的影响。从季节来看,夏、秋、冬季的总云量在西南地区为空间一致的变化趋势,而春季四川盆地北部总云量的变化趋势与其余地区相反;四季总云量也有明显的年变化特征。低云量,全年和四季的时空变化特征相似,由于受地形起伏及区域气候差异的影响,川西高原东部和重庆地区的变化趋势与四川盆地的相反,且同样存在着明显的年际变化特征。另外,突变分析结果显示,西南地区的低云量近 50a 来呈持续减少趋势,而总云量在 1990 年发生突变,突变前在 0 线附近震荡,突变后总云量持续减少。

关键词: 西南地区, 总云量, 低云量, 经验正交函数(EOF)分解, 突变分析

Abstract:

Based on the monthly mean cloud cover data at 73 observation stations in Southwest China from 1956 to 2005,the spatial and
temporal distributions of cloud cover were analyzed by using empirical orthogonal function (EOF) analysis and Mann - Kendall test.
The results showed that the first eigenvectors of annual total cloud cover by EOF in Southwest China were negative consistently,and the
temporal coefficient of the first eigenvector of annual total cloud cover decreased after the 1990s. This means that the change trends of
annual total cloud cover were consistent,and the interannual variation was obvious. Moreover,the second eigenvectors of annual total
cloud cover were different,and the eigenvector values in the east of Southwestern China were negative and positive in the west of South-
western China. It means that the spatial distribution of annual total cloud cover was connected with terrain and climate to some extent.
From the view of seasonal variation,the spatial distribution of total cloud cover in summer,autumn and winter was also consistent,but
that in spring was different,and the change trend of total cloud cover in northern Sichuan Basin in spring was opposite to the rest of
Southwest China. Furthermore,the total cloud cover in four seasons appeared obvious interannual variation. The spatial and temporal
distribution of low cloud cover in four seasons and year was similar,and the change trend of low cloud cover in the east of the western
Sichuan highland and Chongqing was opposite to Sichuan Basin due to the influence of terrain and regional climate. As with the total
cloud cover,the low cloud cover had obvious annual variation. In addition,the low cloud cover over southwest China decreased contin-
uously in past 50 years,but the total cloud cover had a decreasing mutation in 1990.

Key words: Southwestern China, total cloud cover, low cloud cover, empirical orthogonal function, Mann - Kendall test

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