气候变化背景下鄱阳湖流域历史水旱灾害变化特征

收集了鄱阳湖流域公元381~1949年共435 a水旱灾害历史记录。结合历史气候变化的现有研究成果,划分了干旱、湿润历史周期及其起讫时间,根据历史记录承载的信息对水旱灾情严重程度进行科学分级并赋予相应湿润指数值。通过改进水文统计中的P-Ⅲ型频率曲线适线法,分别率定了公元960~1949年期间各湿润、干旱时期湿润指数的均值、方差和离差系数,研究了鄱阳湖流域历史水旱灾害的变化特征。结果表明:公元960~1698年鄱阳湖流域经历了湿润—干旱相间的3个周期,1699~1949年遭遇长达250 a以上的湿润多雨气候。湿润期遭受洪灾年份比旱灾年份多,且大洪灾年数远比于大旱灾年数多;干旱期遭受旱灾年数略多于洪灾年数,但大旱灾年数比大洪灾年数多一些。研究结果对探索鄱阳湖演变、湖区资源开发利用和湿地生态系统演进的历史过程可以提供比较可靠的气候变化依据。

CHANGE CHARACTERISTICS OF HISTORICAL FLOOD AND DROUGHT DISASTERS IN POYANG LAKE BASIN WITH A VIEW TO CLIMATE CHANGE

Data of 435 years records of flood and drought disasters during 381-1949 A.D.in the Poyang Lake basin are collected in this paper.The drought and wet history periods are divided and the start and end times of each period are also determine.The classification of flood and drought disasters are scientifically divided,then the corresponding Moisture Index value is also determined based on historical information carried by the record.The mean value and variance of the Moisture Index in each wet and dry period from 960 to 1949 A.D.are calculated improving the P-Ⅲ frequency curve fitting method.The variations characteristics of the historical flood and drought disasters have been studied.The research showed that there were three periods of wetness-drought in the period of 960-1698 A.D.,then on there were over 250 years of wet and cold climate.During the wet period,the numbers of serious flood year is much mone than the numbers of serious drought year.During the drought period,the numbers of drought years was slightly more than the numbers of flood year,but the numbers of serious drought year is more than the numbers of serious flood year.