钦州湾人工海滩剖面变化过程

波浪和潮汐作用下的海滩剖面动态变化过程是海岸演变及沿海防护工程设计与旅游资源规划的核心内容。本文以广西钦州湾沙井半岛人工海滩为研究区, 基于GPS-RTK采集的2018年1月—2019年12月的逐月剖面高程实测数据, 通过分析剖面冲淤和单宽体积变化, 利用EOF(Empirical Orthogonal Function)函数揭示剖面的高程变化模式, 进而探讨海滩剖面的动态演变过程。研究的主要结果表明: 1) 在观测期间, 人工海滩剖面的冲淤情况整体展现出冬春季淤积、夏秋季侵蚀的变化特征; 2) 人工海滩剖面因泥沙横向输移而导致不同横向分带的单宽体积变化趋势呈差异性, 不同横向分带具有侵蚀与淤积交替出现的情况; 3) 人工海滩剖面的变化模式可划分为由强降雨及台风导致剖面高程明显降低的主要模式、波潮影响下的剖面高程经历强降雨及台风后逐渐淤积和恢复的次要模式、波浪破碎形成卷流引起滩面冲淤变化的其他模式。

Changes of the artificial beach profile in the Qinzhou Bay

The dynamic process of beach profile changes under the actions of waves and tides is the key to understanding coastal evolution, coastal defence design and tourism resource planning. Taking an artificial beach in the Shajing Peninsula of the Qinzhou Bay in Guangxi province as the study area, the study aims to explore the dynamic process of beach profile changes by analyzing the erosion and single-width volume of beach profile, as well as using EOF (Empirical Orthogonal Function) to reveal its model, based on the monthly surveyed profile elevation data from January 2018 to December 2019 using by GPS-RTK, The main results were shown as followed: (1) during the observation period, the artificial beach profile showed a regular variation characterized by accretion in winter and spring and erosion in summer and autumn; (2) due to the transverse sediment transport over the artificial beach, the single-width volumes of beach profile displayed opposite variation trends in adjacent transversal zones, which was manifested by a alternation between erosion and accretion; (3) the variation modes of artificial beach profiles could be divided into three parts that include the main model that beach profile elevations decreased significantly due to heavy rainfall and typhoon, the secondary model that the beach profile recovered gradually after heavy rainfall and typhoon under the influences of tides and normal waves, and the third model that beach profile changes resulted from wave breaking-induced currents under the action of normal waves.