Nonlinear advection, Coriolis force, and frictional influence in the South Channel of the Yangtze Estuary, China

Observation data of along-estuary and lateral current velocities over a transect located at the South Channel of the Yangtze estuary was obtained during a spring tide in August 2011. Harmonic analysis was done on the current velocities to get a mean component and a semi-diurnal component. Based on these two components, the driving mechanisms of mean lateral flow and M 2 lateral tidal flow are shown and analyzed respectively. The dominant driving force of mean lateral flow is nonlinear advection and that of lateral M 2 tidal flow is Coriolis force. The friction plays an important role near the bottom and surface for both lateral mean flow and M 2 tidal flow.