Downward approach to hydrological prediction

Abstract

This paper presents an overview of the 'downward approach' to hydrologic prediction and attempts to provide a context for the papers appearing in this special issue. The downward approach is seen as a necessary counterpoint to the mechanistic 'reductionist' approach that dominates current hydrological model development. It provides a systematic framework to learning from data, including the testing of hypotheses at every step of analysis. It can also be applied in a hierarchical manner: Starting from exploring first-order controls in the modelling of catchment response, the model complexity can then be increased in response to deficiencies in reproducing observations at different levels. The..