明代济南地区旱灾发生频次分析

 通过对明代济南地区历史文献中干旱灾害记载的整理统计,分析了该时期济南地区旱灾的时间变化特征、等级和成因。结果表明,在明代276 a间,济南地区共发生旱灾92次,平均每3 a发生1次。明代济南地区旱灾主要分为两个发生阶段: 1370—1460年代旱灾偏少期和1470—1630年代旱灾多发期。从明代早期到晚期,济南地区旱灾发生频次呈明显增加趋势,而明代中后期旱灾呈较明显的波动变化特点。明代济南地区干旱灾害可划分为4个等级:①以三级大旱灾发生频次最多,为36次,平均每7.7 a发生1次,占旱灾总次数的39%;②一级轻度旱灾和二级中度旱灾,各发生25次和22次,分别占旱灾总次数的27%和24%;③四级特大旱灾发生次数最少,共9次,约占旱灾总次数的10%。气候干旱、降水稀少是旱灾发生的主要原因,人为因素有可能加重了本区旱灾的危害强度。

Frequency of Drought Disasters in Jinan in the Ming Dynasty

Based on statistics of the drought events recorded in historical documents, the temporal distribution, degree and causes of drought disasters in Jinan in the Ming Dynasty (1368—1643) were analyzed in this paper. The results showed that 92 drought disasters, or once every 3 years, occurred in Jinan in the Ming Dynasty. Occurrence of drought disasters in Jinan in the Ming Dynasty can be divided into two main periods: 1368—1460, when the frequency of drought disaster was relatively low, and 1470—1630, when the frequency of drought disaster was relatively high. The frequency of drought disaster tended to increase from the early to the late Ming Dynasty, and also showed obvious variations in the middle and late period. In this region, the serious drought accounted for 39% of the total droughts, the slight drought and moderate drought accounted for 51%, and the worst droughts accounted for about 10%. The high frequency of drought disaster in Jinan in the Ming Dynasty was mainly caused by decreased precipitation, and the frequency and intensity of drought disaster were increased by adverse human disturbances to the environment.