干旱气象

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干旱指数在山西逐日监测中的适用性研究

赵海燕1侯美亭2刘文平1马雅丽1   

  1.  1.山西省气候中心,山西 太原 030006;
    2.中国气象局气象干部培训学院, 北京 100081
  • 出版日期:2014-08-01 发布日期:2014-08-01
  • 作者简介:赵海燕(1980-),女,山西晋城人,博士,工程师,从事灾害区划及影响评估研究.E-mail: zhaohy@ cma.gov.cn
  • 基金资助:

    国家自然科学基金项目( 41201044) 及干旱气象科学研究基金( IAM201207) 共同资助


Application of Drought Index in Daily Monitoring in Shanxi

ZHAO Haiyan1HOU Meiting2LIU Wenping1MA Yali1   

  1. 1.Shanxi Climate Center, Taiyuan 030006,China;
    2.China Meteorological Administration Training Centre,Beijing 100081,China
  • Online:2014-08-01 Published:2014-08-01

摘要:

综合气象干旱指数(CI) 和标准化降水指数(SPI) 在逐日监测中往往会出现干旱突然加重的现象,这是由于某时段内每日降水量对当前干旱的发展贡献是等权重的。本文基于线性递减非等权重的方法对CI 进行了修正,同时对加权降水量(WAP)进行了标准化(Standard WAP Index,SWI) 以山西为例,通过对比CI修正前后,即 CI和CI_new(CI修正后),与SPI和 SWI 在不连续加重现象(UED) 的总体分布典型事例干旱演变特征以及与土壤湿度相关性等方面的差异,分析了4种干旱指数对山西逐日干旱演变的监测能力。结果表明: 1)CI_new 出现 UED 的次数较CI 有了明显下降,SWI出现 UED 的次数也比SPI有了大幅的减少,且SWI 在这4种指数中是出现UED 次数最少的指数; 2) CI_new 和SWI较CI 和SPI与同期土壤湿度的相关性均有所提高,表明修正后的CI_new 和SWI更加符合土壤湿度的变化,更能反映土壤干旱的演变规律。针对干旱发展过程中不连续加重的现象,通过非等权重方法有效地减少了该现象的发生。

关键词: 综合气象干旱指数, 标准化降水指数, 加权降水量

Abstract:

The meteorological composite drought index (CI)and the standard precipitation index (SPI)are usually used as effective daily drought monitoring indexes in the whole country. However,there are many uncontinuous enhancement of drought(UED)in development of drought process at many stations,because daily precipitation in certain period are calculated by equal weighted coefficients in the contribution of present drought development.In fact,the contribution of precipitation today is bigger than that of precipitation twenty nine days ago.In this paper the standard precipitation index (SPI)and the meteorological composite drought Index (CI)were both modified.Modified SPI(SWI)was based on weighted average precipitation (WAP) , and modified CI (CI_new)was calculated by using linear decreasing unequal weight method.Taking an example of Shanxi,overall distribution of UED,daily evolution of typical drought events,and correlations with soil moisture were compared between CI and CI_new,SPI and SWI in order to analyze the monitoring ability of four drought indexes in daily evolution of drought in Shanxi. The results are as follows: (1) The frequency of uncontinuous enhancement of drought (UED)monitored by CI_new and SWI decreased obviously than that monitored by CI and SPI,respectively,and the occurrence times of UED monitored by SWI was least among the four drought indexes; (2) The correlation coefficients between CI_new,SWI and 10 cm,20 cm soil moisture were improved than that between CI,SPI and soil moisture,which confirmed that CI_new and SWI had better accord with soil moisture.Above all,the analysis found that the results monitored by CI_new and SWI are close to actual drought,so CI_new and SWI are suitable for daily drought monitoring in Shanxi.

Key words: meteorological composite drought index (CI) , standard precipitation index (SPI), weighted average precipitation
(WAP)

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