Scaling Analysis for the Interaction between a Buoyant Coastal Current and the Continental Shelf: Experiments and Observations

Abstract

Abstract This paper addresses how the geometrical parameters (ambient ocean depth, H; bottom slope, α) of coastal bathymetry affect the evolution of buoyant coastal currents flowing over a sloping continental shelf. Scaling arguments are presented that show the coastal current dynamics can be classified by a two-variable nondimensional parameter space: the ambient depth parameter, h/H, and the bottom slope parameter, R/yb. The ratio h/H is the fraction of the available depth occupied by the buoyant layer; the bottom slope parameter is the ratio of two horizontal length scales, the internal Rossby radius R to the bottom-trapped width yb. The scale depth h is derived from geostrophic dynamics and is representative of the depth of the buoyant layer of the coastal current. The resulting parameter space is delineated by surface-advected currents that do not depend upon the bottom slope parameter and bottom-trapped currents that do. For bottom-trapped coastal currents, the across-shore width and downstream velo...