一个小型热带河口羽流的季节性变化与洪水事件影响下的特征与动力分析

发布时间：2018-06-10 14:19

  本文选题：河口羽流 + 小河口　； 参考：《热带海洋学报》2017年04期

【摘要】：小河口与大河口的羽流特征具有显著的不同,其更多地受风、径流的变化所控制。文章以海南博鳌万泉河口为例,研究其河口羽流的季节性变化特征,以及洪水对河口羽流的影响。采用动量平衡方法,分析了万泉河口羽流的动力特征。结果表明,万泉河口羽流具有显著的季节性变化,羽流的扩展路径与范围主要受径流和风的控制,夏季时以向外海与向上游方向(相对于开尔文波的传播方向)扩展为主,而冬季时则向下游扩展。夏季的羽流范围大于冬季。一次近2天的洪水可极大地影响羽流的范围及盐度大小,盐度减小1‰的范围可达300km2。但洪水过后,在风与潮汐的混合作用下,河口近岸的盐度可较为快速地恢复到洪水前水平。在羽流的远场区域,流速切线方向主要为压强梯度力与摩擦力的平衡,而在法线方向则为地转平衡;在近场切线方向主要为平流项、压力梯度项与摩擦力项的平衡,而法线方向则主要为压强梯度力与离心力之间的平衡,科氏力项可忽略不计,这与中纬度大河口的近场动力特征具有明显不同。
[Abstract]:The plume characteristics of the small estuary and the big estuary are obviously different, and they are more controlled by the changes of wind and runoff. Taking Boao Wanquan River estuary in Hainan as an example, the seasonal variation characteristics of estuarine plume and the influence of flood on estuary plume are studied in this paper. The momentum equilibrium method is used to analyze the dynamic characteristics of the plume at the mouth of Wanquan River. The results show that the plume in the mouth of Wanquan River has a significant seasonal variation. The plume spreading path and range are mainly controlled by runoff and wind. In summer, the plume extends to the offshore and upstream direction (relative to the propagation direction of Kelvin wave). In winter, it extends downstream. The plume range in summer is larger than that in winter. The range of plume and salinity can be greatly affected by a flood of nearly 2 days, and the range of salinity decrease by 1 鈥，

本文编号：2003515