杭州湾淤泥质海岸岸线变化及其动态模拟

Shoreline Change and Its Dynamic Simulation in the Muddy Coast Area of the Hangzhou Bay

通过对杭州湾北岸南竹港-龙泉岸段实测岸滩断面资料的统计分析,进而对淤泥质海岸岸线变化、影响因素及其动态模拟预报进行探讨。结果表明:因长江来沙减少以及侵蚀/淤积波自东向西移动,导致近10a来该岸段岸滩处于侵蚀状态,其中岸线整体后退;因季节性的波侯作用,岸滩具有冬淤夏冲的特征,岸线则表现为冬涨夏退,因局部工程作用影响的岸线则具有冬退夏涨的特征。此外,基于-3m和-8m等深线构建的径向基函数神经网络模型预报岸线的变化是可行的。

The measured data from a muddy coast segment located from the Nanzhu Harbor to Longquan in the northern coast area of the Hangzhou bay were analyzed statistically.The shoreline change and its influencing factors as well as associated dynamic simulation in the muddy coast segment were discussed.The results show that the beach of the muddy coast segment has been being in an erosion state in recent 10 years due to the decreasing in the incoming sediments from the Yangtze River and the moving of erosion/accretion waves from east to west.This will cause the whole shoreline in the area studied to retreat.Moreover,due to the action of seasonal wave climate,the beach of the muddy coast segment is in a silting state in winter half year and an eroding state in summer half year.As a result,the shoreline is pushed seaward in winter half year and retreated landward in summer half year.However,some parts of the shoreline may be retreated landward in winter half year and advanced seaward in summer half year because of the impacts of local engineering actions.As to the prediction of shoreline changes,it is possible to use the BF neural network mode with input vectors of-3 m and-8 m isobaths.