Fast mechanism-based emulator of a slow urban hydrodynamic drainage simulator. (April 2016)

• Record Type: Journal Article
• Authors: Machac, David; Reichert, Peter; Rieckermann, Jörg; Albert, Carlo
• Is Part Of: Environmental modelling & software. Volume 78(2016:Apr.)
• Page Start: 54
• Page End: 67
• Publication Date: 2016-04
• Subjects: Emulation -- Gaussian process -- Surrogate modelling -- Hydrological models; Environmental monitoring -- Computer programs -- Periodicals; Ecology -- Computer simulation -- Periodicals; Digital computer simulation -- Periodicals; Computer software -- Periodicals; Environmental Monitoring -- Periodicals; Computer Simulation -- Periodicals; Environnement -- Surveillance -- Logiciels -- Périodiques; Écologie -- Simulation, Méthodes de -- Périodiques; Simulation par ordinateur -- Périodiques; Logiciels -- Périodiques; Computer software; Digital computer simulation; Ecology -- Computer simulation; Environmental monitoring -- Computer programs; Periodicals; Electronic journals; 363.70015118
• DOI: 10.1016/j.envsoft.2015.12.007
• Languages: English
• ISSNs: 1364-8152

Abstract

Abstract: Gaussian process (GP) emulation is a data-driven method that substitutes a slow simulator with a stochastic approximation. It is then typically orders of magnitude faster than the simulator at the costs of introducing interpolation errors. Our approach, the mechanism-based GP emulator, uses knowledge of the simulator mechanisms in addition to the information gained from previous simulator runs, so called design data. In this study, we investigate how the degree of incorporating mechanisms into the design of the GP emulator influences emulation accuracy. Similarly to the previous results, we get a significant gain in accuracy already when using the simplest approximation of the mechanisms by a single linear reservoir. However, in this case, we again considerably improve emulation accuracy when using the next two approximations. This allows us to decreases the required number of design data to achieve a similar accuracy as a non-mechanistic emulator. Highlights: We substitute a hydrological model with a faster mechanism-based GP emulator. We compare the gains in emulation accuracy by considering various mechanisms. Already the simplest mechanisms lead to an improvement of emulation accuracy. The emulator leads to a good accuracy already for very small design data sets. The suggested emulator can shorten, e.g., computation time for model calibration.