Investigating Near-Bottom Hydrodynamic Processes in the Yangtze River Estuary Using In Situ Measurements

ABSTRACT Lu, H.; Gu, F.; Qi, D.; Chen, X., and Wang, Y., 0000. Investigating near-bottom hydrodynamic processes in the Yangtze River estuary using in situ measurements. This study aimed to investigate the characteristics of hydrodynamic processes in the near-bottom layer of the Yangtze River estuary to further understand near-bottom hydrodynamic processes in this area. For this purpose, in situ acoustic Doppler velocimetry measurements were taken at two sites (upstream and downstream) during a neap–spring tidal cycle. Results show that tidal asymmetry is significant with wide variations across different areas. The turbulence is anisotropic, and the turbulence pulsation intensity increases with current speed, while turbulence anisotropy weakens. Cd values estimated at both sites vary from 10−4 to 10−2, exhibiting obvious time variation and relationship with current. Their average values are 0.001 and 0.0008, respectively, which are much smaller than 0.0061, which is associated with the local median grain s...