自21世纪以来,由于港口用海、围海养殖等海岸开发活动使得莱州湾岸线发生了显著变化,从而引起了海湾水动力环境的改变.为了探究20年间海湾纳潮量和水交换对莱州湾岸线变迁的响应,本文选取2000年和2020年两个典型年份的莱州湾岸线数据,建立二维潮流与对流—扩散模型,研究20年间莱州湾岸线变迁对海湾纳潮量和水交换的影响.结果表明:2000-2020年20年间,滩涂围填导致海湾潮波势能增加,莱州湾最大可能潮差呈现增大趋势,潍坊港与广利港之间的湾顶增大尤为显著,增加最大值可达8 cm;莱州湾大潮期、小潮期和平均纳潮量分别减小了 2.91％、1.42％和2.33％,海湾面积减少是纳潮量减小的主要原因;由于纳潮海域面积减少,海湾自净能力和水交换减弱,海湾半交换时间增长了 15 d,从海湾局部水交换来看,受港口堤坝建设以及黄河口向海发育影响,海湾西部水交换减弱较为显著,导致西部海域半交换时间增长了 40 d.
Studieson the influence of coastline change on tidal prism and water exchange of Laizhou Bay
Since the 21st century,the coastline of Laizhou Bay has changed significantly due to coastal reclamation activities such as port dam construction and aquaculture dikes,which have caused the change of the hydrodynamic environment of the bay.In order to investigate the response of the tidal prism and water exchange capacity of Laizhou Bay to its coastline change during the past 20 years,the influence of the coastline change on tidal prism and water exchange capacity was analyzed with two-di-mensional flow and advection-diffusion models for the two typical years,2000 and 2020.The results showed that from 2000 to 2020,aquaculture dikes have caused an increase in the potential energy of tid-al waves,and the maximum possible tidal range of Laizhou Bay also shows an increasing trend.The head of the bay between Weifang Port and Guangli Port increased significantly with the maximum in-crease of 8 cm.The spring tidal prism was decreased by 2.91％,the neap tidal prism by 1.42％and the mean tidal prism by 2.33％,and decreased bay area was the main reason for the decrease of tidal prism.The decrease in the sea area of the bay has led to a reduction in its self-cleaning capacity and wa-ter exchange,increasing the bay half-life time by 15 days.As for the local water exchange capacity,the water exchange capacity in the western part of the bay was decreased by port dam construction and a deposition trend of the Yellow River Estuary,resulting in an increase of half-life time in the western part of the bay by 40 d.
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