Published online by Cambridge University Press: 25 December 1997
When a small amount of marked solute is released into a stratified fluid, there is lateral dispersion of the marked solute and a larger lateral dispersion of any density anomaly. The method of moments is used to calculate the two dispersion coefficients. The excess dispersion for the density is shown to be proportional to the fractional density decrease from the bed to the free surface and to the cube of the water depth, and inversely proportional to the vertical mixing for lateral momentum. For weak turbulent mixing the stratification-induced lateral dispersion for the density anomaly can be several orders of magnitude greater than the lateral turbulent mixing for marked solute