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Calibration of conceptual hydrological models revisited: 1. Overcoming numerical artefacts
journal contribution
posted on 2023-05-18, 02:20 authored by Kavetski, D, Kuczera, G, Franks, SWConceptual hydrological modelling has traditionally been plagued by calibration difficulties due to the roughness and complex shape of objective functions. These problems led to the abandonment of powerful classical analysis methods (Newton-type optimisation, derivative-based uncertainty analysis) and have motivated extensive research into nonsmooth optimisation and even new parameter estimation philosophies (e.g. GLUE). This paper shows that some of these complexities are not inherent features of hydrological models, but are numerical artefacts due to model thresholds and poorly selected time stepping schemes. We present a numerically robust methodology for implementing conceptual models, including rainfall-runoff and snow models, that ensures micro-scale smoothness of objective functions and guarantees macro-scale model stability. The methodology employs robust and unconditionally stable time integration of the models, complemented by careful threshold smoothing. A case study demonstrates the benefits of these techniques.
History
Publication title
Journal of HydrologyVolume
320Issue
1-2Pagination
173-186ISSN
0022-1694Department/School
School of EngineeringPublisher
Elsevier Science BvPlace of publication
Po Box 211, Amsterdam, Netherlands, 1000 AeRights statement
Copyright 2005 Elsevier Ltd.Repository Status
- Restricted