武威地区清代-民国时期干旱灾害特征研究

通过对历史文献资料的搜集与整理,利用统计分析和小波分析的方法,对武威地区清代-民国时期干旱灾害的等级序列特征、年代际变化、季节变化、周期变化及成因进行了研究。结果表明:武威地区清代-民国时期共发生旱灾70次,平均每4.4年发生1次。干旱灾害以中度旱灾为主,占旱灾总次数的60%,其次是大旱灾,占旱灾总次数的20%,轻度旱灾和特大旱灾发生频率较低,各占旱灾总次数的14.3%和5.7%。清代-民国时期武威地区干旱灾害呈现先增加后减少再增加的趋势。旱灾在季节上以夏旱次数最多,其次为夏秋连旱。旱灾存在5～8a周期、8～10a周期、15a周期、20～25a周期、50a周期。清代-民国时期旱灾的发生是人类活动与气候变化共同作用的结果。

Characteristics of drought disasters in Wuwei region during the Qing dynasty and the Republic of China

Water resource has key position in arid area in northwest China,especially in inland river basin.In order to balance the contradiction between dry climate and more and more use of water resource,researches on the law of drought disaster have great significance to solve the water problem in scare water area.Based on collection and arrangement of historical material,hierarchical sequence features,decadal change,seasonal change,periodic variation and reason of drought disaster were analyzed using the methods of statistic analysis and wavelet analysis for the Wuwei Region during the Qing dynasty and the Republic of China.The results showed that there were 70 times drought disasters in total,approximately once every 1.97 years on average.Drought disasters were mainly moderate ones,which accounted for 60% of the total,followed by big drought disasters accounted for 20% of the total,and that serious and mild ones accounted for 5.7% and 14.3% of the total respectively were lower frequency.Drought disaster could be divided into there periods,it had features with gradually increase in the first phase form 1640s to 1760s;drought disaster had tendency with slowly decrease in the second phase form 1770s to 1880s;It became rise gradually again from 1890s to 1940s in Wuwei Region during the Qing dynasty and the Republic of China.Drought disaster mainly occurred in summer,followed by successive summer and autumn drought.Drought disasters in Wuwei Region during the Qing dynasty and the Republic of China has inter-annual and inter-decadal oscillations like 5～8 a,8～10a,15a,20～25a and 50a.Drought disaster in Wuwei Region were the result of the cooperation of human activity and climate change.