根据汉江上游洪水事件的地质沉积记录和历史文献记载,统计分析了北宋时期汉江上游地区的洪水发生频率及其影响,并对该历史时期气候变化进行分析。通过对汉江上游安康东段立石村(LSC)剖面、郧县西段五峰段李家咀(LJZ)剖面、郧县西段尚家河(SJH)剖面的洪水沉积剖面分析,判定在950—1050 A.D.的北宋时期汉江上游地区确有特大古洪水事件的地质沉积记录。根据历史文献资料的搜集和整理,说明北宋时期确实为洪水灾害频发时期。对洪水灾害的气候背景分析表明:在950—1050 A.D.间气候发生恶化转折,气候状态不稳定,降水变率增大,导致了汉江上游的特大洪水事件的发生。
By camparison of records collected from extraordinary flood event sediments with statistic results of the historical documents in the upper reaches of the Hanjiang River in different historical periods, the flood frequency and the climate change during the Chinese Northern Song Dynasty are analyzed. Through comparison of the LSC, LJZ,SJH sedimentary sections in the upper reaches of the Hanjiang River,the SWDs were dated to 950--1050 A. D. ,which just was the Northern Song Dynasty (from 960 A.D. to 1127 A. D. ). Then,based on the collection of historical document data, results showed that the Northern Song Dynasty was indeed the frequent flooding period. Because the instable climatic condition, the precipitation variability increases, it occurred extraordinary floods in the upper reaches of the Hanjiang River.