Vertical Diffusion in Shallow Waters

From tracer measurements in stratified, shallow waters with a vertical current shear the vertical diffusion coefficient is determined. Two different models are used, treating separately the cases of strong and weak vertical stratification. The diffusion coefficient is related to the stratification, the frictional stress, and the shear. With a persisting wind of strength above 4–5 m/s, the stress in the upper layer is assumed to be proportional to the wind stress. In this special case the theoretical and experimental results can be compared, and a good agreement is found.