To a methodology for model validation

Eulerian grid models are used to calculate the ozone formation in the troposhere over Europe. It is of primary importance, both from a scientific point of view as well as in establishing the benefits of abatement strategies by using these models, to be able to determine the reliability of these models. Currently, no consistent and generally accepted method exists to determine this reliability. Comparing measured with calculated ozone concentrations at the same location is insufficient for determining the performance of models. Multicomponent analysis and assessment of observed phenomena are essential ingredients of a methodology for model validation.