粤东海域海洋动力作用较强, 平均波高 0.9—1.3m, 最大碎波水深 5.9—10.0m, 海流流速 10—60cm·s ?1 。粤东岬湾海岸剖面中段处于侵蚀演变态势。文章基于海陆相互作用下的界面理论, 阐述了在大浪或强浪情况下, 碎波带波浪水动力强度最大值和底剪应力的分布及其对海底沉积物搬运和造成地形侵蚀的机理; 另外, 在海流作用下, 海洋水团底层流速所形成的底剪应力亦可引起海底基岩侵蚀和沉积物的搬运堆积, 改变地貌形态。文章最后得出岬湾海岸剖面变化的 2 种基本模式, 即基岩海岸岬角剖面形态发育模式和湾内沉积性海岸剖面形态发育模式。前者剖面上部为陡壁, 下部呈缓凹型; 后者剖面为凹型, 滨线有一定进退演变。

The ocean dynamic is strong in the eastern Guangdong waters, with mean wave height of 0.9?1.3m, maximum surf water depth of 5.9?10.0m, and current velocity of 10?60cm·s ?1 . The middle part of the coastal section at the eastern Guang- dong headland-bays is in an obvious eroding state. Using the interface theory based on sea-land interaction, the author ex- pounds the mechanism of bottom shear stress by waves to erode seabed and convey sediments under the circumstances of rough sea or very rough sea. In addition, under the effect of ocean currents, the bottom shear stress that is formed due to bot- tom current velocity may also lead to seabed erosion and sediment transition and deposition, and then change landforms. In conclusion, the author presents two basic modes of this kind of coastal sections, namely, mode of rock headland section, with upper section being steep and lower section being slowly concave, and mode of sedimentary section within the bay, with a concave section and changeable shoreline.