Lagrangian study of floating debris transport around the Pearl River Estuary in summer

Transport of floating debris around the Pearl River Estuary (PRE, China) in summer is investigated by using drifter trajectories, a regional ocean model and a particle tracking model. Comparisons between simulated and drifter trajectories demonstrate that the particle tracking model accurately simulates the movement of floating debris. Ideal experiment results show that 85 % of floating debris is stranded in the PRE due to density currents, tidal currents, and wind effects. The west side of Shenzhen and the west side of Hong Kong are identified as high-risk retention areas. Approximately 15 % of floating debris disperses into open waters, with significant contributions from the east side of Macau and areas outside the eastern four river outlets of the PRE. The combined effect of density currents and winds is considered the primary driver in the movement of floating debris and a series of management measures are proposed accordingly.