Guinot V. auteur aut IRD Cappelaere Bernard auteur aut IRD Delenne C. auteur aut IRD Ruelland D. auteur aut IRD text journalArticle eng text/pdf born digital access Calibrating conceptual hydrological models is often done via the optimization of objective functions serving as a measure of model performance. Most of the objective functions used in the hydrological literature can be classified into distance- and weak form-based objective functions. Distance- and weak form-based objective functions can be seen respectively as generalizations of the square error and balance error. An analysis of the objective functions shows that: (i) the calibration problem is transformed from an optimization problem with distance-based objective functions into a root finding problem for weak form-based functions; (ii) weak form-based objective functions are essentially less prone to local extrema than distance-based functions; (iii) consequently, they allow simple gradient-based methods to be used; (iv) parameter redundancy can be assessed very simply by superimposing the contour lines or comparing the gradients of two objective functions of similar nature in the parameter space; and (v) simple guidelines can be defined for the selection of the calibration variables in a conceptual hydrological model. The theoretical results are illustrated by two simple test cases. Weak form-based approaches offer the potential for better-posed calibration problems, through the use of a number of independent criteria that matches the dimension of the identification problem. In contrast with distance-based objective functions, they do not have the inconvenience of solution non-uniqueness. Finally, the need for models with internal variables bearing a physical meaning is acknowledged. specialized Model performance evaluation Calibration Objective function Mean squared error Nash-Sutcliffe efficiency Conceptual hydrological model 062 401 1-2 1-13 2011 0022-1694 https://www.documentation.ird.fr/hor/fdi:010053501 10.1016/j.jhydro.2011.02.004 0022-1694 [F B010053501] https://www.documentation.ird.fr/hor/fdi:010053501 https://www.documentation.ird.fr/intranet/publi/2011/05/010053501.pdf Accès réservé (Intranet de l'IRD) IRD - Base Horizon / Pleins textes 2011-05-31 2024-01-15 fdi:010053501 fre