Effects of Wave–Current Interactions on Suspended-Sediment Dynamics during Strong Wave Events in Jiaozhou Bay, Qingdao, China

Abstract

Wave–current interactions are crucial to suspended-sediment dynamics, but the roles of the associated physical mechanisms, the depth-dependent wave radiation stress, Stokes drift velocity, vertical transfer of wave-generated pressure transfer to the mean momentum equation (form drag), wave dissipation as a source term in the turbulence kinetic energy equation, and mean current advection and refraction of wave energy, have not yet been fully understood. Therefore, in this study, a computationally fast wave model developed by Mellor et al., a Finite Volume Coastal Ocean Model (FVCOM) hydrodynamics model, and the sediment model developed by the University of New South Wales are two-way coupled to study the effect of each wave–current interaction mechanism on suspended-sediment dynamics near shore during strong wave events in a tidally dominated and semiclosed bay, Jiaozhou Bay, as a case study. Comparison of Geostationary Ocean Color Imager data and model results demonstrates that the inclusion of just the combined wave–current bottom stress in the model, as done in most previous studies, is clearly far from adequate to model accurately the suspended-sediment dynamics. The effect of each mechanism in the wave–current coupled processes is also investigated separately through numerical simulations. It is found that, even though the combined wave–current bottom stress has the largest effect, the combined effect of the other wave–current interactions, mean current advection and refraction of wave energy, wave radiation stress, and form drag (from largest to smallest effect), are comparable. These mechanisms can cause significant variation in the current velocities, vertical mixing, and even the bottom stress, and should obviously be paid more attention when modeling suspended-sediment dynamics during strong wave events.

Effects of Wave–Current Interactions on Bay–Shelf Exchange

“…Both the half-life time (Table 1) and the cross-section flux (Table 2) indicate the WRS plays the most important role in the bay-shelf exchange among the proposed wave-current interactions. Previous work by Gao et al (2018) also found the WRS may alter the current velocity significantly, even though the three-dimensional WRS proposed by Mellor (2003Mellor ( , 2015 missed the divergence of vertical flux associated with nonhydrostatic pressure perturbations (Ardhuin et al, 2017). In this study, the residual current between Exp1 and Exp8 (No WRS) also shows the most significant difference (Figure 8c), which is almost equal to the difference between Exp1…”

“…The coupling between waves and currents includes depth-dependent wave radiation stress, Stokes drift velocities, vertical transfer of wave-generated pressure to the mean momentum equation caused by the form drag, wave dissipation as a source term in the TKE equation, mean current advection and refraction of wave energy, and combined wave-current bottom stress (Mellor 2003;Mellor et al 2008;Mellor 2015). Details on the two-way coupling between the MDO wave model and the FVCOM hydrodynamic model can also be found in Gao et al (2018). It has been proved computationally efficient and well validated in theoretical experiments, and successfully applied in Lake George, Australia, Gulf of Mexico Shen, 2010, 2012) and Jiaozhou Bay,…”

“…The bottom stress induced by the wave orbital velocities and its interaction with the current-induced bottom stress were addressed to be significant to the sediment suspension and transport (e.g., Tang and Grimshaw, 1996;Wiberg and Sherwood, 2008;Song et al, 2013;Gao et al, 2018). However, its impact on the bay-shelf exchange is…”

Design, construction, and application of a regional ocean database: A case study in Jiaozhou Bay, China

“…In addition, Gao et al (, ,b) developed hydrodynamics, wave, and sediment models for JZB based on the coastline in 2008, which will also provide further modeling data for the JZB database.…”

The influence of physicochemical environment on the distribution and abundance of mangrove gastropods in Ngurah Rai Forest Park Bali, Indonesia

“…The study site at station 1 and station 4 which were on the coastal area so that the influence of sea current can affect the substrate fraction composition. According to Eddy and Roman (2016); Gao et al (2018);Soler et al (2020), which the stronger current will be found coarse granules. Conversely, in waters with the weak current will be found smooth granules will be deposited.…”