厦门岛东南岸沙滩近期剖面变化研究

A STUDY ON RECENT CHANGES OF BEACH PROFILES ALONG SOUTHEAST SHORE OF XIAMEN ISLAND, FUJIAN PROVINCE, CHINA

根据厦门岛东南岸沙滩剖面1999年2月—2002年11月4年的观测资料,分析了该剖面上平均高潮位、平均海平面、平均低潮位的位置变化,绘制了冲淤变化曲线,研究剖面的形态特征及季节和长周期变化趋势。结果表明,风暴潮影响后沙滩剖面呈风暴型剖面,而常浪季节均表现为滩肩型复式剖面。受滨外地形、岸线走向、季节性风浪和潮汐活动等因素影响,沙滩剖面的季节变化比较复杂,长周期变化及风暴潮后剖面的恢复过程各岸段有所不同:泥沙流上游的岸段供沙不足,呈侵蚀状态,剖面恢复较慢;下游则呈基本稳定或淤长状态,剖面恢复相对较快。暴风浪和季节性常风浪交替作用控制着本区沙滩剖面的长周期循环变化过程,该过程一般包括风暴侵蚀期、快速恢复期、稳定恢复期和基本稳定期4个阶段。

Based on the survey data of beach profiles along the southeast shore of Xiamen Island in the past 4 years from Feb 1999 to Nov 2002, the position changes of MHW, MSL and MLW along the profiles were analyzed by drawing their scouring-silting curves, and their shape characteristics, seasonal changes and long-period changing trend were studied.The results showed that the beach profiles belonged to the type of storm profile during storms and of berm profile during other seasons. Affected by many factors such as offshor eterrain, coast trend, seasonal waves and tide activity, etc, the seasonal changes of the profiles were comparatively complicated. There were some differences in long-period changing trend and after-storm recovering process between different coast sections. The upper sections, due to lack of sand provision, were basically in a eroding state and recovered comparatively slowly; the lower sections were basically in a stable or silting-up state and recovered comparatively quickly. The alternating action of storms and ordinary seasonal waves controlled the long periodic beach changing process, which commonly comprised four stages, i e. fleetly eroding stage, fast recovering stage, steadily recovering stage and approximately stable stage.