华南沿海海滩状态和演变

根据华南沿海不同区域和不同形态海滩的地形和碎波参数计算分析，得出本区存在着４种平均海滩状态：（１）消散优势型海滩；（２）沿岸坝－槽型海滩；（３）沿岸坝沟或低潮阶地型海滩；（４）反射优势型海滩。华南海滩状态除有长期的侵蚀趋势外，存在明显的季节演变，它与波浪作用的变化关系密切；此外，人为建造的海岸工程也可引起海滩状态的变化，今后在其开发利用中必须予以注意。

BEACH PHASES AND EVOLUTION IN THE COASTS OF SOUTH CHINA

long the coasts of South China waves are formed by the monsoon and tropical cyclones.Throughout the year predominant wave directions are NE-SE with 0. 5-1.3m average wave heights and 3.0-5. 15 saverage periods. During Nov. -Apr., wave height,period and sand-transport capacity are larger than in May-Oct., and there exists some regional differences.In accordance with land forms and surf parameters of different regions and various beach morphologies in the coasts of South China, there exists 4 types of average beach phases:1.Dissipative domain beach 1 2. Longshore bar-trough beach;3. Longshore barditch or low tide terrace beachl 4. Reflective domain beach.Except for long-term erosion tendency in the beach phases of South China, there is a clear seasonal evolution which is closely related with seasonal change by wave action.Besides, man-made coastal engineering can lead to change in the beach phase,which should be noticed in future development.