热带气旋前进方向两侧海滩风暴效应差异研究——以海滩对0307号台风“伊布都”的响应为例

Study on the Difference Between Storm Effects of Beaches on Two Sides of the Tropical Cyclone Track——Taking the Responses of Beaches to No.0307 Typhoon Imbudo as an Example

在0307号台风"伊布都"(Imbudo)袭击华南沿海前后,对相距约300km的高栏岛飞沙湾(位于气旋前进方向右侧)和水东港下大海(位于气旋前进方向左侧)的固定海滩剖面地形及滩面沉积物进行了对比调查。调查结果表明,右侧海滩地形受台风暴浪冲击发生剧烈变化:后滨陆侧堆积,后滨向海侧及前滨滩面侵蚀(单宽侵蚀量达55m3/m,平均海面(MSL)位置蚀退13m,岸线位置蚀退5m),以致剖面类型由滩肩式断面向沙坝式断面转变,表现出了海滩对台风做出快速响应;而左侧海滩剖面地形基本保持原状,虽也略呈侵蚀,但冲淤变化不大,表现为对台风做出迟缓响应。同时,从动力、滨海输沙、滩面沉积物变化和海岸地貌等方面对两侧海滩明显差异的风暴效应的机制进行了探讨。

The comparison between and investigation on the topographies of fixed beach profiles and beach face sediments in the Feisha Bay of the Gaolan Island and at Xiadahai, situated about 300km apart and on the right and left sides of typhoon track, respectively during No.0307 typhoon Imbudo attacking were made. It is shown from the investigation results that the beach topography on the right side had changed greatly due to the impact of typhoon-induced storm wave, the landward backshore accreted, and the seaward backshore and foreshore beaches were eroded (the profile erosion reached 55m^3/m, the mean sea level (MSL) mark retreated up to 13m, and the shoreline retreated up to 5m) so that the profile type had changed from berm type to bar type, which shows the rapid response of beach to typhoon; but the beach profile on the left side had changed slightly with a weak erosion and small change in scour and fill, which shows the slow response of beach to typhoon. The mechanism for the difference between storm effects of beaches on two sides is explored in terms of dynamics, littoral sand transport, changes of beach face sediments and coastal geomorphology.