Automatic calibration of the tank model / L'étalonnage automatique d'un modèle à cisterne

Abstract

The automatic calibration is done not by a hill-top climbing method but by a trial and error method carried out automatically by a computer program. The feedback procedure is made by comparing some criteria obtained from the observed hydrograph and the calculated hydrograph output from the working tank model. The two criteria are discharge volume and the shape of the hydrograph. The feedbacks of these two criteria correspond to dispacement feedback and velocity feedback in automatic control. The output of the working tank model is composed of components, the outputs from each of the tanks. Correspondingly, the whole period is divided into subperiods, in each of which each of the components plays the main part. The volume and shape are calculated in each subperiod and are used for the adjustment of the respective tanks. The feedback procedure starts from some initial model and converges very quickly after several (usually less than 15) iterations, and the result obtained is very good.