伶仃洋河口横向环流

摘要

Lateral circulation ,w hich can be generated in estuarine systems by a variety of mechanisms ,plays an im‐portant role in the momentum balance and mass transport in estuaries .A three‐dimensional hydrodynamic model (EFDC) ,combined with field measurement data in 1989 and 2002 ,is used to investigate the lateral circulation in the Lingding Estuary .The model have successfully reproduced the hydrodynamics and salinity distribution during the flood and dry seasons .Two cross‐sectional profiles in two different regions are chosen to examine the lateral circu‐lation and salinity dynamics in different periods .The results show that lateral circulation is poorly developed in the Lingding Estuary and features more local characteristics because of its special bathymetry and hydrodynamic condi‐tions .T he lateral circulation in the Lingding Estuary is generated by the interaction among river flow ,tidal currents and bathymetry ,and the mechanisms in two sections are different .In this study ,we conclude that lateral circulation is not significant for the dynamics of Lingding Estuary .%横向环流存在于大多数河口中，在河口的动量平衡和物质输运过程中起着重要的作用，其形成的机制众多。本文利用三维水动力模型EFDC（Environmental Fluid Dynamics Code），结合1989年和2002年的实测数据对伶仃洋河口进行研究，得到了伶仃洋河口在洪季和枯季时期不同的水动力和盐度分布结构。在文中选取了具有代表性的两个断面，针对洪枯季、大小潮以及涨落潮等不同时期的横向流结构和盐度剖面分布特点进行比较和分析。结果显示，受局地的径、潮流条件和地形约束影响，横向环流结构并不能充分形成，在不同的区域表现出截然不同的结构特点。伶仃洋河口横向环流主要是在径、潮流与地形三者之间的相互作用下形成的，不同的区域的形成机制存在差异。综合分析后，本文认为伶仃洋河口的横向环流在该区域的动力过程中相对较为次要。