长江三角洲及其附近地区两千年来水灾的研究

通过对长江三角洲及其附近地区两千年来水灾生成频率和强度的分析。认为两晋、南北朝时期和南宋、元、明、清时期是两千年来本区的主要水灾期。对照两千年来中国东部气候变化、海面升降与长江口河道变迁关系,认为在本区水灾生成事件中,气候因素起着主导控制作用。当然,人类活动对本区水灾生成的影响也不容忽视。本地区近百年来的旱涝灾害规律可用非线性科学的方法进行研究,旱涝灾害的准60年、准35年和准11年的长周期变化与地球自转速度、地极移动和太阳黑子活动的3个周期变化基本一致。本地区气候系统的行为具有混沌特征。这是线性逼近和周期叠加预报方法难以得出灾害预报正确结果的原因,但气候系统半个月的确定性预测可以实现。

Research on flood hazard in the Yangtze Delta and its nearby area since the early Anno Domini

According to the analysis of flood hazard frequency and intensity in the Yangtze Delta and its nearby area since the early Anno Domini, this paper suggests that the periods in Jin, South and North, South Song Dynasties as well as Yuan, Ming and Qing Dynasties are the main flood disarster periods. The authors consider the relation among the climate change, sea level fluctuation and the Yangtze River mouth migration since the early Anno Domini, suggest that the climate factor is a major control factor to form flood disarster in this area. The influence of the human being ac- tivities to form the flood hazard in this area can not be ignored. It is found that the climate system has chaos attractor, and at the turn-point, it is controlled by 3-5 factors. Because the quasi-period of 60, 35 and 11 years of the flood and drought disasters is same as that of earth rotation velocity, polar migration range and solar action, we consider that the 3 above factors are the main driving el- ements. This study shows that the traditional forecasting methods of period accumulation and trend extension could not get the correct results.