Observation of Sediment Dynamics in the Nearshore Region using Fluorescent Sand Tracers
Observation of Sediment Dynamics in the Nearshore Region using Fluorescent Sand Tracers
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DOI：
10.3811/jjmf.2019.t003
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发表时间：
2019-03
期刊：
影响因子：
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通讯作者：
Takayuki Suzuki
中科院分区：
文献类型：
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作者：
Takayuki Suzuki
利用荧光沙示踪剂于2014年和2015年在日本滨崎海岸进行了风暴波条件下从冲积带到外滩近海的跨岸泥沙输移的现场观测。两年数据集的地形差异在于，2014年存在外滩形态，2015年不存在。在观测过程中，观测了波高和波周期，并进行了砂芯取样。利用观测到的波浪资料和从岩心采集的荧光示踪剂的分析结果，研究了风暴期间泥沙从外沙坝区近海一侧到冲荡带的运动。结果表明，沙尘暴过程中泥沙运动受外滩形状的影响。如果存在外坝，则外坝岸侧的沉积物倾向于向陆地移动，也会由于底流的作用而向海移动，直到外坝位置。外沙洲近岸一侧的泥沙由于推移质泥沙的输运，倾向于向岸上方向移动。然而，谷区的输运率有所下降。没有沙洲形态的海滩地形，槽区推移质输沙率高于沙洲地形。因此，沙洲近海一侧的沉积物也可以移动，直到潮汐。
Takayuki Abstract The field observations of cross-shore sediment transport from the swash zone to the offshore side of the outer bar using fluorescent sand tracers were conducted in 2014 and 2015 at the Hasaki coast, Japan facing the Pacific Ocean during storm wave conditions. The topography difference between the two years data set is that outer bar shape existed in 2014 and not existed in 2015. During the observations, wave height and wave period were observed, and sand core samplings were conducted. By using the observed wave data and the analyzed results of collected fluorescent sand tracers from the cores, the sediment movements from the offshore side of the outer bar area to the swash zone during storms were investigated. The results indicate that the sediment movements during the storms were affected by the outer bar shape. If the outer bar existed, the sediment of the onshore side of the outer bar tend to move landward, and it also moves to seaward due to undertow until the outer bar location. The sediment at the offshore side of the outer bar tends to move to onshore ward due to bedload sediment transport. However, the transport rate decrease in the trough region. The beach topography without the bar shape, the bed load sediment transport rate at the trough region was higher than that with the bar shape. Thus, the sediments at the offshore side of the bar also could move until the swash