海南岛莺歌海近岸的潮汐不对称与潮致余流研究

发布时间：2018-12-27 11:12

【摘要】：潮汐不对称与潮致余流在河口海岸区的物质输运中扮演着重要角色。已往的研究表明,在驻波占主导的河口海湾中,涨落潮的历时不对称与流速不对称有较为良好的对应关系。而潮致余流主要由地形与潮波的非线性作用所致。本研究以海南岛莺歌海附近为代表,结合实际观测与数值模型,研究复杂地形的开阔近岸区的潮汐不对称与潮致余流。结果表明,在莺歌海近岸区,涨落潮历时不对称皆表现为涨潮历时短于落潮历时,而流速不对称则出现复杂的空间变化。对流速不对称的机制分解表明,研究区的流速不对称主要由K_1、O_1与M_2的相互作用,以及潮余流与各潮汐分潮的相互作用所控制。其中前者产生涨潮流速大于落潮流速的涨潮优势,而后者则与余流的方向相对应,出现多个涨潮优势与落潮优势的区域。总体而言,研究区的流速不对称由余流与各潮汐分潮的相互作用所决定。这表明,采用涨落潮历时的不对称来确定潮汐不对称的方法在开阔近海区可能并不适用。对潮致余流的研究表明,研究区的欧拉余流远大于斯托克斯余流。欧拉余流表现为多个顺时针与逆时针的涡流。涡流分布与地形具有较好的对应关系,潮流沙脊区多发育顺时针涡流,而深槽区则以发育逆时针涡流为主。摩擦力在涡流的发育中起着重要作用。
[Abstract]:Tidal asymmetry and tidal residual currents play an important role in mass transport in estuarine and coastal areas. Previous studies have shown that in the estuarine bay dominated by standing waves, the diachronic asymmetry of the fluctuating tide has a good relationship with the asymmetry of the velocity. The residual tidal current is mainly caused by the nonlinear interaction between topography and tidal waves. Taking the Yinggehai area of Hainan Island as a representative, combined with practical observation and numerical model, the tidal asymmetry and tidal residual currents in open coastal areas with complex topography are studied. The results show that in Yinggehai inshore, the asymmetry of tide duration is that the duration of tide is shorter than that of falling tide, and the asymmetry of velocity is complicated spatial variation. The mechanism of velocity asymmetry decomposition shows that the asymmetry of velocity in the study area is mainly controlled by the interaction between Ks _ 1 / O _ 1 and M _ s _ 2, and the interaction between tidal residual current and tidal component. In the former, the tidal current is higher than that of the falling tide, while the latter is corresponding to the direction of the residual current, and there are several areas where the tidal current is dominant and the ebb tide is dominant. In general, the asymmetry of velocity in the study area is determined by the interaction between the residual current and the tidal component. It is suggested that the method of determining tidal asymmetry by using the asymmetry of the fluctuating tide duration may not be applicable in the open coastal area. The study of tidal residual current shows that the Euler residual current in the studied area is much larger than the Stokes residual current. Euler's residual current is represented by multiple clockwise and counterclockwise eddies. The eddy current distribution has a good corresponding relationship with the topography. In the tidal current and sand ridge, there is a clockwise eddy current, while in the deep trough area, the counterclockwise eddy current is the main one. Friction plays an important role in the development of eddy current.
【作者单位】：海南省海洋与渔业科学院;中山大学海洋学院;
【基金】：广东省重点基金(2014A030311046)
【分类号】：P731.2

【参考文献】