ABSTRACT
A model of dispersion can be anything that presents an image of the physical phenomenon of spreading in the sea, more or less accurate or even largely simplified. If the basic concept of the model is a set of differential equations, the method of solving may become rather dominating and appear in the name of the model or the model type, e.g. "grid model", "finite difference model", "finite element model", "superposition model". The rectangular grid of a finite difference model has a limited capacity for adaption to coastline shape and orientation. Models may be divided in classes from many different viewpoints. These include number of dimensions, stationarity, tools, mathematical method, problems dealt with, purpose and so on. Two-dimensional vertical models can be useful in estuaries and as a tool for numerical modeling of vertical mixing but not as direct means for description and prediction of dispersion in the sea.
