Combined Effect of Tides and Wind on Water Exchange in a Semi-Enclosed Shallow Sea

Abstract

The Bohai Sea is a semi-enclosed shallow sea in China, where the tides and wind are the dominant factors contributing to the water exchange with the Yellow Sea. However, existing studies on this water exchange primarily consider only the effect of tidal action, neglecting the contribution of wind. In this study, numerical models were used to simulate the hydrodynamic processes and tracer transport, with the consideration of both tides and wind. Based on the models, the two time scales, age and half-life, are applied to study the water exchange in the Bohai Sea quantitatively. The results show that the age and half-life decrease significantly when wind is included in the simulation, revealing that wind is an important contributor to the water exchange in such a semi-enclosed shallow sea. Under the combined forcing of tides and wind, the water transport in the Bohai Sea becomes clockwise, in contrast with the counterclockwise transport driven by the tides only. The seasonal-varying wind leads to a fluctuation of water exchange in an annual cycle, with the stronger water exchange in the northern (Liaodong Bay) and the western (Bohai Bay) regions of the Bohai Sea in winter and in the southern part (Laizhou Bay) in summer.

Measurements and modeling of water levels, currents, density and wave climate on a semi-enclosed tidal bay: Cádiz (SW Spain)

“…The influence of freshwater discharges is weak since the mean discharge rates are approximately 20 m 3 /s compared to a tidal prism of 10 5 m 3 /s. With these characteristics, the Bay of Cádiz is considered an example of tidally-dominated, shallow, semi-enclosed bays (Kitheka, 1997;LEE et al, 1997;Newton et al, 2014;Shang et al, 2019).…”

Consistent Boundary Conditions for Age Calculations

“…These expressions can also be obtained by setting K = 0 in ( 22) and ( 23) and dealing with the resulting equations in the sense of distributions. Calculating the age from the concentration and age concentration by solving the relevant equations under consistent initial and boundary conditions is generally much easier than evaluating the (mean) age from the age distribution function, which is why many studies relying on CART simply did so [39,47,65,69,[73][74][75][76][77][78][79][80][81][82][83][84][85][86][87][88]. However, we must bear in mind that this approach may veil some of the subtleties of the transport phenomena under study.…”

Three‐Dimensional Water Exchanges in the Shelf Circulation System of the Northern South China Sea Under Climatic Modulation From ENSO

“…These waters and the associated environmental health are essentially affected by the shelf circulation and the exchanges with the open ocean (Allen & Durrieu de Madron, 2009; Malan et al., 2022). For example, water exchange is a determining physical process for water renewals of coastal waters and a high water exchange rate promotes the self‐purification of coastal waters (Pitcher et al., 2010; Ranjbar et al., 2019; Shang et al., 2019; Yuan et al., 2021), largely reduce the time scale of the hypoxia in the coastal water (Fennel & Testa, 2019), and play a key role in the global cycle of carbon (Bauer et al., 2013; Regnier et al., 2022). Meanwhile, seasonal variations in coastal water exchange are associated with the rapid expansion of algal blooms, thus also provides important information for coastal zone management (Lin et al., 2022).…”