Spectral structure of horizontal water movement in shallow seas with special reference to the North Sea, as related to the dispersion of dissolved matter

The spectral structure of horizontal water movements in a shallow sea like the North Sea is reflected in the horizontal spreading phenomena. In the present paper results from tracer experiments in the North Sea are combined with model simulations in order to improve the insight in the relative importance of the variations in the horizontal water movements, the vertical shear dispersion and the 3D turbulence. It is tried to obtain estimates of the kinetic energy spectrum of the horizontal eddies. The analysis of the role of the main mechanisms of mixing and dispersion also applies to other shallow tidal seas, and to an extent, to the mixed upper layer of the oceans. The models used are briefly described.