J4 ›› 2010, Vol. 28 ›› Issue (4): 384-390.

• 论文 • 上一篇    下一篇

西藏高原汛期不同等级降水变化特征分析

王传辉1唐晓萍2吴萍1   

  • 收稿日期:2010-07-14 修回日期:2010-08-06 出版日期:2010-12-31 发布日期:2010-12-31
  • 作者简介:王传辉(1984-),男,在读硕士,主要从事区域气候变化研究.E-mail:wang_chh@yahoo.cn
  • 基金资助:

    “近百年来我国极端天气气候事件变化特征及其影响”(2007BAC29B02)和“中国气候系统的协同观测与预测研究”项目(GY-HY200706005)共同资助

Characteristics of Different Intensity Precipitation in Flood Season over the Tibetan Plateau

 WANG Chuan-Hui1, TANG Xiao-Ping2, TUN Ping1   

  1. (1.Key Laboratory of Meteorological Disaster of Ministry of Education,Nanjing University of Information Science&Technology,Nanjing 210044,China;2.Shapingba Meteorological Bureau of Chongqing,Chongqing 400030,China)
  • Received:2010-07-14 Revised:2010-08-06 Online:2010-12-31 Published:2010-12-31

摘要:

根据西藏25个台站近37 a(1973~2009年)的逐日降水资料,利用线性倾向估计以及Morlet小波变换等方法对高原汛期(5~9月)不同等级降水日数进行分析。结果表明:(1)西藏高原降水主要由小雨和中雨组成,两者雨量相当,大雨不到降水总量的10%;(2)在空间分布上,高原降水日数与小雨日数相似,由雅鲁藏布江下游向四周递减,高原西北部最少;中雨和大雨由雅鲁藏布江流域向南北2侧递减;(3)在时间演变上,总降水日数与小雨日数在各季节分配均匀,而中雨和大雨则均有明显的季节差异,主要集中在6月下旬至8月中旬。近37 a来,总降水日数和小雨日数存在明显的年代际变化,具有准12~13 a的年代际周期;小雨日数呈减少趋势,而中雨呈增加趋势,总降水日数和大雨日数无明显增加和减少;(4)在降水日数变化趋势的空间分布上:总降水和小雨日数在雅鲁藏布江以及高原东部地区以减少趋势为主;而高原西北部以增加趋势为主。在高原大部分地区中雨和大雨日数以增加为主,中雨日数减少的地区主要位于高原南部边缘地区,而大雨日数减少的地区主要位于高原东部。

关键词: 西藏高原, 汛期降水, 不同等级降水日数, 周期特征, 变化趋势

Abstract:

Based on the daily precipitation data of 25 stations in Tibet from 1973 to 2009,rainy days with different level precipitation in flood season over the Tibetan Plateau were analyzed using the methods of linear trend and Morlet wavelet transform.Results show that it was mainly the light and moderate rain over the Tibetan Plateau.The light rainfall was almost equal to the moderate rainfall but the heavy rainfall was less than 10%of the total rainfall.The spatial distribution of light rainfall days was very similar to that of the total rainfall days over the Plateau,which decreased from the downstream of the Yarlung Zangbo River to surrounding regions,and rainfall was the least over the northwest of the Plateau.While the moderate and the heavy rain days declined from Yarlung Zangbo River basin to the north and south sides.The moderate and the heavy rainfall days presented an apparent seasonal change,which concentrated mainly in late June to mid-August.The total and light rainfall days has decadal cycle with quasi-12-13-year.The light(moderate)rainfall days showed a decreasing(increasing)trend.But the total and the heavy rainfall days showed no significant increasing or
reducing trend.The trend of rainfall days was quite different in spatial distribution,the total and light rainfall days decreased mainly in Yarlung Zangbo River and the eastern Plateau,while increased in the southern Plateau.In most parts of the Plateau moderate and heavy rainfall days mainly increased.Moderate rain days reduced in the southern marginal areas and heavy rain days reduced in the eastern Plateau.

Key words: the Tibetan Plateau, precipitation in flood season, rainfall days with different levels, cycle characteristics, trend

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