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1 历史上旱灾及其特点 从历史资料来看,建国前,济宁季旱、连年干旱现象经常发生,每百年间发生旱灾达50余次,平均不到两年发生一次大旱灾。1785～1787三年连续大旱,“运河干涸”、“微山湖无水”、“旱情严重”、“民不聊生”。建国后,由于降水量持续减少,气温逐渐升高,干旱频率越来越高,旱情愈来愈严重。特别是近20年来,枯水期和平水期循回交替,降水总量不足,干旱问题严重。1987～1990年南四湖上级湖连续四年出现
1 Historical Drought and Its Characteristics Historically, before the founding of the People’s Republic of China, the drought in Jining was frequent and successive years of drought often occurred. Droughts hit more than 50 times in every 100 years, with an average drought of less than two years. 1785 ~ 1787 Three consecutive years of drought, “the canal dried up”, “Weishan Lake anhydrous”, “a serious drought”, “people are boring.” After the founding of the People’s Republic of China, the drought was aggravating due to the continuous decrease of precipitation, the gradual temperature rise and the increasing frequency of drought. Especially in the past 20 years, the dry season has returned to a period of peace and water cycle, the total amount of precipitation has been insufficient and the drought problem has been grave. From 1987 to 1990, the superior lake of Nansi Lake appeared for four years in succession