渤海岸线及水深变化对水动力影响的数值模拟

Numerical Simulation of the Hydrodynamics Affected by Coastline and Bathymetry Changes in the Bohai Sea

为探究渤海岸线及水深变化对水动力的影响,基于Delft3D水动力学模型,选用2003年和2015年作为围填海前后的典型年份,建立了围填海前后岸线及水深条件下的渤海三维水动力模型,并对水动力场进行了模拟。通过对围填海前后潮波和潮余流的分析,得到了岸线及水深变化对渤海水动力场的影响。结果表明:填海后,岸线及水深变化会对渤海主导分潮M2分潮产生较大影响,秦皇岛附近无潮点向西北方向偏移,渤海海域M2分潮振幅总体减小;潮致余流场受岸线及水深变化影响较大,其中渤海湾曹妃甸港南部形成复杂的涡流,沿岸海域余流增大;滨海新区附近形成多个小范围环流,且天津港到黄骅港北部沿岸海域2015年余流比2003年增加3~5 cm/s;黄骅港南部形成一个逆时针环流,并且该处余流减小2~5 cm/s。辽东湾辽河口附近由于水深增加导致余流减小2~7 cm/s。莱州湾黄河口附近的逆时针环流向东南方向移动,黄河口北部余流略有减小,东南部余流明显增大,增加量最多能达到9 cm/s。刁龙嘴南侧顺时针环流减小,北侧顺时针环流增大4~9 cm/s。

In order to explore the influence of coastline and bathymetry changes on the ocean hydrodynamic field,the three-dimensional hydrodynamic model of the Bohai Sea under present(2015)and historical(2003)coastline and bathymetry conditions were constructed based on the Delft3D-FLOW model,and the hydrodynamic conditions of the Bohai Sea were simulated accordingly.The simulated tidal wave and tidal residual current were compared and analyzed,and the influence of coastline and bathymetry changes on the dynamic field of the Bohai Sea was explored.The simulation results showed that the changes of coastline and bathymetry had noticeable impact on the M2 tidal wave system in the Bohai Sea.After reclamation,the amplitude of the M2 tide decreased and the amphidromic point near Qinhuangdao shifted to the northwest.The tide-induced Eulerian residual current was affected by the coastline and bathymetry changes.The residual current in the southern of Caofeidian Port exhibited irregular changes,formed complex eddies,and increased in the offshore area.The residual current from the Tianjin Port to the northern coastal area of the Huanghua Port increased by 3-5 cm/s in 2015 compared to that in 2003.A counterclockwise circulation formed in the southern part of Huanghua Port,and the residual current decreased by 2-5 cm/s.As the water depth increased,the residual current decreased by 2-7 cm/s near the Liaohe Estuary of the Liaodong Bay.The counterclockwise current near the Yellow River Estuary moved to the southeast,the residual current in the northern part of the Yellow River Estuary decreased slightly,and the residual current in the southeast significantly increased by up to 9 cm/s.The clockwise circulation on the south of the Diaolongzui decreased,and the clockwise current on the north increased by 4-9 cm/s.