甘肃白银市近500年旱涝特征及变化趋势分析

The Analysis of Drought and Flood Characteristics and Its Trend in Baiyin City of Gansu in Recent 500 Years

利用研究区域近500年旱涝历史记录及1949-2008年后实测资料,根据文献提供的旱涝等级划分数据,对该地区1470-2008年的旱涝特征、变化趋势进行了统计分析。结果表明,研究区域539年的统计时段内,发生旱、涝灾害的年份分别为214年和76年,正常年份为249年。从旱涝发生频次的￥年际变化看,总体旱涝特征为旱灾多于涝灾,旱涝发生次数均有逐年增多的趋势。旱涝发生周期为:主周期为40年,其次有49年、60年、31年、8年和2~4年等。

Based on the historical records of drought and flood in the study area for nearly 500 years and the measured data from 1949 to 2008,this paper makes a statistical analysis of the characteristics and trend of drought and flood in this area from 1470 to 2008 according to the data of drought and flood classification provided by the literature.The results showed that in the statistical period of 539 years,the years of drought and flood disasters were 214 years and 76 years,respectively,and the normal years were 249 years.From the interannual variation of the occurrence frequency of drought and waterlogging,the overall characteristics of drought and waterlogging are that drought is more than flood,and the occurrence frequency of drought and waterlogging has a trend of increasing year by year.The main cycle is 40 years,followed by 49 years,60 years,31 years,8 years and 2~4 years.