Mechanism and application of the Lagrangian flow network method to indicate practical material distribution patterns in the tide-dominated Bohai Sea with multi-frequency tides

Abstract

Mass transport process is vital for the spatial distribution of materials in coastal environments, and comprehending this process is essential for efficient marine pollution control and environmental conservation. As tides is an essential process in coastal environments, the patterns of practical material distribution are decoded in the tide-dominated Bohai Sea with multi-frequency tides by employing the Lagrangian flow network (LFN). Here, the parameter of degree represents the mass transport process, and the concept of the hydrodynamic province is used to depict the spatial distribution of passively transported materials. The emergent pattern of hydrodynamic provinces driven by multiple tidal constituents aligns with the climatological salinity trend, pollutant distribution and phytoplankton community in the springtime Bohai Sea, demonstrating the practical utility of the LFN. The mechanism elucidated by the LFN can be mainly attributed to the intertidal Lagrangian residual velocity induced by tides. Particularly in spring, the tide-induced residual current in the Bohai Sea significantly contributes to basin-scale circulation, while the wind-driven component in winter and the thermohaline part in summer play a more important role than those in spring. In the realm of marine management and conservation strategies, taking into account both terrestrial and maritime perspectives, and incorporation of the marine mass transport process is crucial for the formulation of effective policies.