通过对汉江上游辽瓦店(LWD) 、前坊村(QFC) 、庹家洲(TJZ)全新世沉积剖面分析,判定在1 900 ~ 1 700 a B. P. 的东汉时期(25220 A. D.),汉江上游有发生过洪水事件的记录。根据历史文献资料的搜集和整理,说明东汉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: 东汉时期汉江上游地区的气候恶化转折,气候状态不稳定,降水变率增大,导致了汉江上游的洪涝灾害发生。
英文摘要:
The Hanjiang River is located in a region between the temperate and subtropical zones,and it is sensitive to environmental change. The river valleys are mostly U-shaped,deep and narrow,the stream is torrential, and the storage capacity is low. Therefore,flood disasters occur frequently in the Hanjiang River Basin. As a water source of the South-to-North Water Transfer Project,the negative change of precipitation and meteorological conditions in the upper reaches of the Hanjiang River will endanger the security of peoples lives and impact the local economic development,thus more and more researches focused on this field. In this paper,the LWD,QFC and TJZ Holocene sedimentary profiles in the upper reaches of the Hanjiang River were analyzed,the SWDs were dated to 1 900-1 700 a B. P. in the Eastern Han Dynasty (from 25 A. D. to 220 A. D.). Based on the statistic results of the historical data and records in the upper reaches of the Hanjiang River,the flood disasters during the period from 221 B. C. to 618 A. D. were analyzed. The conclusion was that the flood frequency was the highest in the Eastern Han Dynasty. The flood occurrence was related to the unusual climate fluctuation and the unstable weather system.