海平面上升—夹河断流背景下烟台套子湾海滩砂粒度变化

Change of Sand Particle Size in Taoziwan Beach in Yantai City under the Background of Sea Level Rise—Jiahe River Cutoff

摘要:

将烟台套子湾2021年与2005—2006年夹河口东西两侧海滩砂的粒度特征进行对比分析，揭示了近16年来套子湾海滩沉积物粒度特征变化对全球海平面上升—夹河入海水沙减少等过程的具体响应。研究表明，现代套子湾海滩砂样品以中砂、细砂为主，分选极好或好，标准偏差介于0.23~0.4，夹河口东侧的海滩砂平均粒径（Mz：1.39~1.64Φ）比西侧海滩砂平均粒径（Mz：1.47~1.91Φ）粗，主要组分中的粗砂和中砂含量比西侧高，表明现代夹河口东侧区域水动力较夹河口西侧强，该区海滩砂受到海洋动力的长期改造分选较好。近16年夹河口两侧海滩砂粒度明显粗化，表现在海滩砂平均粒径变粗、主要组分粒度变粗约0.5Φ、概率累积曲线的粗细截点变粗0.5~1Φ及滚动、跃移、悬移组分含量明显变化。夹河入海物质减少，海平面快速上升，导致海洋动力增强是研究区海滩砂粒度粗化、海滩侵蚀的主要原因，该研究结果可以为套子湾海滩防护提供科学指导。

Abstract:

In this paper, the grain size characteristics of beach sand on the east and west sides of Jiahe estuary in Yantai Taozi Bay in 2021 and 2005—2006 have been compared and analyzed, and the specific reflection of the change of grain size characteristics of beach sediment in Taoziwan beach to the process of global sea level rise and water and sediment reduction into the sea of Jiahe River in recent 16 years have been revealed. It is showed that the beach sand samples of modern Taoziwan beach are mainly medium sand and fine sand, and the sorting is excellent or good. The standard deviation is 0.23~0.4, and the beach sand average particle size (Mz: 1.39~1.64Φ) on the east side of Jiahe estuary are more coarse than sand average particle size on the west beach (Mz: 1.47 ~ 1.91 Φ）. The content of coarse sand and medium sand in the main components is higher than that in the west. It is indicated that hydrodynamic force in the east of modern Jiahekou is stronger than that in the west of Jiahekou. The beach sand in this area is well sorted by long term transformation of marine power. In recent 16 years, the beach sand on both sides of Jiahe estuary has coarsened obviously. The average particle size of beach sand has coarsened and the particle size of main components has coarsened by about 0.5Φ.The coarse and fine cut-off points of the probability accumulation curve become thicker by 0.5~1Φ, and the contents of rolling, jumping and hanging components changed significantly. The main reasons for the coarsening of beach sand and beach erosion in the study area are the reduction of substances in Jiahe River into the sea and rapid rise of sea level. The research results can provide scientific guidance for the beach protection of Taoziwan beach.