明代(公元1368—1644年)钱塘江河口潮灾时空分布及其影响因素

钱塘江河口是世界著名强潮河口。基于历史文献资料,系统梳理考证了明代(公元1368—1644年)钱塘江河口潮灾记录,分析了潮灾的空间、时间分布特征:(1)北岸潮灾远多于南岸,海门以上河口段与海门以下河口段潮灾次数基本持平,但均少于河口湾段。(2)潮灾在南北两岸的空间分布上,存在转移与变迁,由此导致两岸分别存在明显的平缓期—爆发期—平缓期交替,但平缓期与爆发期的时长并不固定。(3)潮灾强度变化与潮灾频次分布有较强关联,高强度潮灾多发于潮灾频发期。结合历史气候、江道地形等自然环境背景,探讨了影响潮灾时空分布的要素,认为钱塘江潮灾发生的频次及规模大小与流域内干湿变化及历史气温升降有明显关联,而历史极端潮灾则常是多种要素耦合的结果。

Spatial and temporal distribution of tidal disasters in Qiantang River estuary during Ming Dynasty (AD 1368-1644) and its influencing factors

Qiantang River is famous in the world for its strong tidal estuary in the world. Based on historical documents,this paper summarized the distribution characteristics of tidal disasters across time and space. Firstly,tide disasters occurred more frequently in the north shore compared with the south shore. The number of tidal disasters hitting the upstream of Haimen was not significantly different from that for the downstream of Haimen,although both of estuaries had smaller numbers of tidal disasters when comparing with the Qiantang Estuary. Secondly,tide disasters distribution in space has changed,leding to an apparent successive variations between stable period and eruptive period, but the length of the stable period and eruptive period was not fixed. Thirdly,the intensity change of tidal disasters was quite strongly related to their frequency distribution. High strength tidal disasters occurred more frequently during the eruptive period. Additionally,this paper discussed the influencing factors on the tidal disasters distribution across time and space, in combination with the natural environment background,such as historical climate,channel topography and so on. Results of this study suggests that the frequency and grade of tidal disasters of Qiantang River are related to the changes of historical rainfall and temperature in this area. However,the extreme tidal disaster was caused by the coupling processes of multiple factors.