海口湾波浪漫滩区及其邻近水域悬沙观测特征初步分析

波浪漫滩是海滩上水陆分界线随波峰向岸推进,随波谷向海回退的现象,它是近年来海岸水沙运动研究的前沿科学问题,其水沙运动观测分析更是需要优先研究的课题。选择海口湾假日海滩,在2013年11月下旬进行了波浪漫滩区及其邻近水域悬沙观测,观测结果表明:1在进行漫滩流速分析时,分别对上爬和回退的平均速度进行统计,两个坡度下上爬速度大于回退速度分别占80%和65%,说明波浪漫滩过程上爬速度通常要大于回退速度;2波浪漫滩区比邻近水域的平均含沙量高1 000倍左右;3波浪漫滩区内从海向岸的悬沙浓度逐渐降低,下界(靠海侧)、中间位置、上界(靠岸侧)的平均悬沙浓度分别为67 059.6mg/L、50 290.9 mg/L、15 762.0 mg/L;4波浪漫滩区悬沙浓度变化随机性强,对其测量和特征分析提出了更高的要求。

Preliminary observation of the suspended sediment in the swash zone and its adjacent area of Haikou Bay

Swash is the phenomena that the waves move the instantaneous shoreline back and forth, which is the key problem of the coastal dynamical and sediment research in the recent years. The priority research of swash should be put in the observation of dynamics and sediment. The observation of suspended sediment in the swash zone and its adjacent area of Haikou Bay was done in November 2013. The results show some conclusions. Firstly,the analysis of velocities in the swash zone with two slopes show, the average velovities of swash rundown which are bigger than the velocities of swash runup account for the number of twenty percent and thirty-five percent percent of the total groups respectively ,the velocities of swash runup are more often big than the velocities of swash rundown in the swash zone .Secondly, the average suspended sediment concentration in the swash zone is about 1000 times higher than that in its adjacent area. Thirdly, the suspended sediment concentration in the swash zone gradually reduces from the sea to the shore, it is 67059.6mg/L in the lower (near the sea) of the swash zone, 50290.9mg/L in the middle of the swash zone and 15762.0mg/L in the upper (near the shore) of the swash zone. Fourthly the variation of suspended sediment concentration in the swash zone is in strong randomness, which brings strict requirement on the further suspended sediment observation in the swash zone