Wind-driven circulation patterns in a shallow estuarine lake: St Lucia, South Africa
Wind-driven circulation patterns in a shallow estuarine lake: St Lucia, South Africa
复制标题
DOI：
10.1016/j.ecss.2014.05.007
复制
发表时间：
2014-06
影响因子：
2.8
通讯作者：
J. Schoen;D. Stretch;K. Tirok
中科院分区：
文献类型：
--
作者：
J. Schoen;D. Stretch;K. Tirok
风驱动的环流模式和相关的水交换或停留时间的时空结构可以驱动重要的生物流体动力学的相互作用在浅水湖泊和河口。南非的圣卢西亚河口湖就是这种系统的一个例子。它是联合国教科文组织世界遗产和拉姆萨尔湿地的国际重要性，但没有详细的研究，其流通模式以前已经进行。在这项研究中，一个水动力学模型被用来调查这些循环的结构，以提供他们在运输和水交换过程中的作用的见解。一个强大的昼夜时间模式的风速，以及两个主导方向之间的方向切换，驱动间歇性的水交换和湖泊盆地之间的混合。“浅水近岸区域的高速流动与较深区域的较慢逆风逆流，由循环环流联系在一起，是环流的关键特征。这些模式受到圣卢西亚复杂几何形状和系统收缩的强烈影响。水交换的时间尺度是不均匀的，一些流域末端有相对较长的停留时间。讨论了环流模式对生物过程的影响。
The spatiotemporal structure of wind-driven circulation patterns and associated water exchanges or residence times can drive important bio-hydrodynamic interactions in shallow lakes and estuaries. The St Lucia estuarine lake in South Africa is an example of such a system. It is a UNESCO World Heritage Site and RAMSAR wetland of international importance but no detailed research on its circulation patterns has previously been undertaken. In this study, a hydrodynamic model was used to investigate the structure of these circulations to provide insights into their role in transport and water exchange processes. A strong diurnal temporal pattern of wind speeds, together with directional switching between two dominant directions, drives intermittent water exchanges and mixing between the lake basins. “High speed flows in shallow nearshore areas with slower upwind counter-flows in deeper areas, linked by circulatory gyres, are key features of the circulation”. These patterns are strongly influenced by the complex geometry of St Lucia and constrictions in the system. Water exchange time scales are non-homogeneous with some basin extremities having relatively long residence times. The influence of the circulation patterns on biological processes is discussed.