Simultaneous Calibration of Hydrologic Model Structure and Parameters Using a Blended Model. Issue 5 (3rd May 2021)

• Record Type: Journal Article
• Authors: Chlumsky, Robert; Mai, Juliane; Craig, James R.; Tolson, Bryan A.
• Is Part Of: Water resources research. Volume 57:Issue 5(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-05-03
• Subjects: blended model -- model calibration -- hydrologic modeling -- model structure; Hydrology -- Periodicals; 333.91
• DOI: 10.1029/2020WR029229
• Languages: English
• ISSNs: 0043-1397

Abstract

Abstract: The advent of hydrological modeling frameworks that support multiple model structures using the same software enables both model structure and model parameters to be calibrated and assessed. To date, the identification of optimal model structure has typically been performed manually. Here, a continuous (rather than discrete) treatment of model structure is used, which enables simultaneous automatic calibration of model structure and parameters using a conventional real‐valued decision variable optimization algorithm (the dynamically dimensioned search algorithm, DDS). The method, referred to herein as blended model structure calibration (BMSC), relies upon the calculation of each hydrologic flux (e.g., for infiltration) as a weighted average of fluxes generated from multiple process algorithm options. This method is applied to 12 lumped MOPEX catchment models and compared to the calibration of 108 fixed model structures, representing all possible permutations of fixed model structures with the given process options in this study. The BMSC method consistently identified near‐optimal model structure (as evaluated using average model rank performance) at significantly lower computational cost than calibrating the collective of fixed structure models. The BMSC method also provides a useful tool in identifying dominant processes and model structures in catchments. Key Points: Model structure and parameters may be calibrated simultaneously using the blended model structure calibration (BMSC) method The BMSC method consistently identified near‐optimal model structures at significantly lower computational cost than fixed structures This method may also be useful in identifying dominant processes and model structures in catchments