Permalink : http://hdl.handle.net/2115/42763

KEYWORDS : estuarine circulation;upper mixed layer;anti-cyclonic gyre;potential vorticity conservation

Under the baroclinic process influenced by the Earth's rotation in enclosed coastal seas, Fujiwara et al. (1997) suggested that anti-cyclonic gyre (negative vorticity) was generated in the upper mixed layer by the horizontal divergence associated with upward entrainment, which was part of the estuarine circulation. They theoretically show that such vorticity (ζ) is close to a spatial uniform value of ζ=-f/2 (f>0 is the Coriolis parameter) at the steady state. However, this solution is basically given by infinitely small thickness of water column according to the potential vorticity conservation. We propose the revised solution in the finite upper mixed layer (H), i.e., ζ=-fx/[x+(u0/w0)H] is the increasing function of offshore distance from a river mouth (x) and depends on the ratio of river inflow velocity (u0) to upward entrainment velocity (w0).