摘要
海岸侵蚀与水动力之间有着密切的关系。基于现场调查和资料收集,探讨了吕四海岸地貌、水动力、泥沙运动以及沉积与动力之间的响应。研究结果表明,风浪和潮流是塑造吕四海岸的主要动力。风浪年内变化按向岸风频率可分为高频期(10月至翌年1月)、转频期(2月、3月和9月)和低频期(4～8月)三个时期。风浪高频期,潮滩冲蚀,物质粗化;低频期,潮滩淤积,物质细化;转频期,时冲时淤,动态稳定。潮流作用主要表现为输沙淤滩和侧蚀滩脚。在风浪高频期,滩脚同时受到风浪冲蚀和潮流侧蚀,向岸后退,使吕四岸段成为隐性侵蚀型海岸。岸滩塑造对沉积动力响应显著,东部处于滨岸环境,在潮流和风浪的作用下,沉积物由岸向海变粗;西部还受径流影响,处于滨岸-河口环境,物质由岸向海变细。在水动力要素中,风浪是导致岸滩侵蚀的主控动力,而潮流则是近岸泥沙进行滩槽滩槽交换和循环输运的输运动力。
There is a close relationship between coast erosion and hydrodynamics. Based on observation and measured data, it will be revealed that the rules of topography, hydrodynamics, sediment transportation and sediment dynamics at the Lusi coast. The results indicate that： Lusi coast is mainly shaped by wind waves and tidal currents. Classified by shoreward wind frequency, wind wave annual changes should be classified in a high frequency period featured by erosive tidal fiat and coarser sediment particles, a low frequency period charactered with silting beach and finer sands, and a transitional period in which the coast reaches to the dynamic balance between scour and silting. Tidal currents can not only transport sands to silt at the tidal fiat, but also scour the tidal fiat root laterally. Especially, in the high frequency period, the tidal fiat root will fall back with both wind waves and tidal currents scouring. In the end, Lusi coast turns into recessive erosive coast. The coast shaping has made a good response to the hydrodynamics. Under the combined action of waves and tidal currents, the east is in bank environments, where the grain size has a changing tendency from coarse to fine. However, the west of the coast is in bank-estuary environments with the opposite grain size changing tendency due to the action of river currents. Consequently, in plenty of hydrodynamic factors, wind waves become the primary power leading the coast to be scoured, and tidal currents are the transporting power to dominate the moves of sands between tidal fiat and deep trough.
出处
《海洋通报》
CAS
CSCD
北大核心
2009年第3期53-61,共9页
Marine Science Bulletin
基金
海洋公益性行业科研专项经费项目(200705020)
我国近海海洋综合调查与评价(908-01-ZH2)(908-02-03-04)
关键词
吕四
沉积动力
沉积物
泥沙运动
海岸侵蚀
Lusi coast
sediment dynamics
surface sediment
sediment transportation
coast erosion
