Both longitudinal and lateralϕ-advections are intermittent at the North Passage in the Changjiang River estuary.
Large lateralϕ-advection may be enhanced by large lateral gradient of ϕ there.
Large longitudinal depth-mean straining overlays the effects of tidal straining, circulation and river discharge there.
Large lateral depth-mean straining may be generated by large lateral density gradient interacting with the shear flow there.
Longitudinal non-mean straining, lateral non-mean straining and vertical advection are relatively smaller there.