Rip currents under obliquely incident wind waves and tidal longshore currents
Rip currents under obliquely incident wind waves and tidal longshore currents
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斜入射风波和潮汐沿岸流下的离岸流
DOI：
10.1016/j.coastaleng.2014.04.001
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发表时间：
2014
影响因子：
4.4
通讯作者：
J. V. T. D. Vries
中科院分区：
文献类型：
--
作者：
G. Winter;A. Dongeren;M. D. Schipper;J. V. T. D. Vries
在荷兰海岸进行了一项关于离岸流性质的实地实验，该实验与以前的离岸流研究地点不同，因为它是一个以风-海为主的环境，大部分是斜入射波和潮汐驱动的沿岸流。在实验过程中，三个不同的流动模式，获得与GPS跟踪漂流仪器，观察到：（1）一个本地控制的循环单元，（2）离岸流，是偏离海岸平行的碎波带外，（3）蜿蜒的长海岸流。从撕裂流（流型1和2）到弯曲沿岸流（流型3）的过渡逐渐发生在潮汐周期内，沿岸流在中高潮盛行。在这个网站上出现的裂流在冲浪区酒吧的凹陷，通常发生在当水位下降到NAP（相当于MSL）以下，即使在存在斜入射波和潮汐驱动的沿岸流。用数值模型XBeach对漂流物实验进行了后报模拟，结果与现场观测结果吻合良好。该模型随后被用来研究潮汐水位波动，沿岸流和斜入射波对离岸流的影响。离岸流开始时，水位下降到一个特定的阈值与离岸流的大小与水位。潮流的强度及其相对于入射波的方向决定了离岸范围和离岸流的方向。与其他研究表明，离岸流只发生在海岸正常（或略斜波），在这项研究中，观察和数值模型模拟表明，离岸流可以存在于大角度的波浪入射，当离岸通道是足够宽，波高是小的。
A field experiment on the nature of rip currents was conducted on the Dutch coast, which differs from previous rip current study sites because it is a wind-sea dominated environment with mostly obliquely incident waves and tidally-driven longshore currents. During the experiment three distinct flow patterns, obtained with GPS tracked drifter instruments, were observed: (1) a locally governed circulation cell, (2) an offshore current that is deflected shore parallel outside the surf zone and (3) a meandering longshore current. The transition from rip currents (flow patterns 1 and 2) to meandering longshore currents (flow pattern 3) occurred gradually within the tidal cycle with longshore currents prevalent at mid to high tide. Rip currents at this site appeared at depressions in the surf zone bar and typically occurred when the water level fell below NAP (equivalent to MSL), even in the presence of obliquely incident waves and tidally driven longshore currents. Hindcast simulations of the drifter experiments were performed with the numerical model XBeach and showed good agreement with field observations. The model was subsequently used to investigate the influence of tidal water level fluctuations, longshore currents and obliquely incident waves on rip currents.Rip currents were initiated when the water level dropped below a specific threshold with the magnitude of the rip current associated with the water level. The strength of the tidal current and its orientation with respect to the incident waves governed the offshore extent and orientation of the rip current. In contrast to other studies that suggest that rip currents solely occur under shore normal (or slightly oblique waves), in this study both observations and numerical model simulations indicate that rip currents can exist under large angles of wave incidence, when the rip channel is sufficiently wide and the wave height is small.
影响因子：
2.3
作者：
Austin, Martin J.;Masselink, Gerd;Russell, Paul E.
通讯作者：
Russell, Paul E.
影响因子：
2.9
作者：
J. MacMahan;Jeff L. Brown;Jenna A. Brown;E. Thornton;A. Reniers;T. Stanton;M. Henriquez;E. Gallagher;J. Morrison;M. Austin;T. Scott;N. Sénéchal
通讯作者：
J. MacMahan;Jeff L. Brown;Jenna A. Brown;E. Thornton;A. Reniers;T. Stanton;M. Henriquez;E. Gallagher;J. Morrison;M. Austin;T. Scott;N. Sénéchal