Figure 3

Empirical spatio-temporal variogram and fitted theoretical spatio-temporal variogram. Empirical spatio-temporal variogram (left part of the image) describes spatial, temporal and also spatio-temporal relations that can be found in the sample data. The fitted theoretical spatio-temporal variogram (right part of the figure) shows the fitting of the theoretical metric model that tries to describe all relations by mathematically defined function with estimated parameters. The horizontal axis shows the distance among data points in space; vertical axis displays the time distance and semivariance (the power of the relations) is expressed by the colour scale. The theoretical model approximates the real data mainly at closer distances in both, space and time.