1644-1911年宁夏西海固干旱灾害时空变化及驱动力分析

通过对历史文献资料的收集、统计和分析,对1644-1911年西海固地区干旱灾害的时间变化、空间变化、等级序列以及驱动力因子进行了研究。结果表明:1644-1911年西海固地区有记载的干旱灾害82次,平均3.27年发生一次;旱灾以春旱和夏旱最多,占发生次数的38.5%和25.3%;西海固地区的干旱灾害划分出四个等级序列,共发生轻度旱灾24次,占旱灾总数的29.3%;发生中度旱灾50次,占旱灾总数的60.97%;发生大旱灾和特大旱灾共8次,占旱灾总数的9.73%;西海固发生干旱灾害可分为5个阶段:旱灾的多发期包括:1710-1770年代、1800-1860年代(1820年代除外)。少旱灾期包括:1640年代-1700年代、1780-1790年代、1870-1910年代(1890年代除外);这一时期的中期西海固发生干旱灾害发生频率较高;旱灾高发区主要集中在西海固与陕西交接的南部,其中固原发生干旱的频次远远高于其他地区;影响干旱灾害时空变化的驱动力因子包括气候、生态和人口因子,其中气候因子起到了决定的作用。

Analysis on the dynamic changes of drought disasters and the driving factors in Xihaigu,Ningxia during 1644 to 1911

Through the collection and analysis to the historical materials of Xihaigu,Ningxia between 1644 and 1911,the disaster rank,the time variation,spatial variation and driving factors were studied in this paper.The results showed that between 1644 and 1911 the drought disasters in Xihaigu altogether had 82 times and averagely occurred one time per 3.27 year.The drought occurred in spring and summer were the most,and which were 38.5% and 25.3%.The grade sequence of dry disasters was divided into four classes.The light drought took up 29.3%.Middle drought were 50 times and accounted for 60.97%;The strong droughts were accounted for 9.73%.The drought occurred between 1644 and 1911 could be devided into five phases.The frequent drought in occured in 1730-1780era(except1760era),1810-1860era(except 1830era).Less period of drought occured in 1640-1720era,1790-1800era,1870-1910era;The change tendency of drought disasters in Xihaigu had remarkable increaced in late period.The drought area mainly concentrates on the south of XiHaigu.The drougth occurrence in Guyuan was higher than other areas.The effect driving factors of the dry disaster time and space changes included climate,ecosystem and population.