莱州湾西南部岸线变迁对海域水动力影响的数值研究

20世纪70年代以来，盐田、养殖围堤、港口堤坝建设等开发活动使莱州湾西南部岸线变迁尤为显著，从而引起了海湾水动力环境的改变。为探究近50年莱州湾水动力环境对海湾西南部岸线变迁的响应，本文建立二维数值模型，研究莱州湾西南部3个时段岸线变迁对海湾潮流、纳潮量和水交换的影响。结果表明，1968－2020年莱州湾西南部流速变化以减小为主，流速变化较大的区域主要位于盐田或养殖围垦区和新建港口附近海域。近50年，莱州湾纳潮量呈逐年减小趋势，大潮、中潮、小潮和全潮平均纳潮量分别减少5.85%、7.28%、8.85%和6.47%，围填海是导致纳潮量减小的主要原因。1968－2010年莱州湾整体的水交换能力有所提高，2010－2020年则相差很小；从局部看，1990－2020年港口附近海域的水交换能力均显著降低。

Numerical study on hydrodynamic effects of coastline changes in southwestern Laizhou Bay

Since the 1970s, the coastline of the southwestern Laizhou Bay has changed greatly mainly due to the reclamation activities such as salt fields, aquaculture dikes and port dam construction, which have caused the changes of the hydrodynamic environment of Laizhou Bay. In order to investigate the response of the hydrodynamic environment of the Laizhou Bay to its southwestern coastline changes during the past 50 years, the influence of the southwestern coastline changes on tidal current, tidal prism and water turnover capacity has been analyzed for three stages through two-dimensional numerical model. The results showed that the variation of flow velocity is mainly decreased in the southwestern Laizhou Bay from 1968 to 2020. The areas with large variation of velocity were mainly located in salt fields or aquaculture reclamation areas and sea areas near newly-built ports. In the past 50 years, the tidal prism of Laizhou Bay has decreased year by year. From 1968 to 2020, the spring tidal prism was reduced by 5.85%, the middle tidal prism by 7.28%, the neap tidal prism by 8.85% and the mean tidal prism by 6.47%, and reclamation is the main reason for the decrease of tidal prism. As for the overall water turnover capacity of the Laizhou Bay, it has been improved from 1968 to 2010, but there is little change between 2010 and 2020. As for the local water turnover capacity, the water turnover capacity around the port levees area was significantly reduced in 1990-2020.