Details zur Publikation |
| Kategorie | Textpublikation |
| Referenztyp | Zeitschriften |
| DOI | 10.5194/hess-22-1299-2018 |
Lizenz  |
|
| Titel (primär) | Combining satellite data and appropriate objective functions for improved spatial pattern performance of a distributed hydrologic model |
| Autor | Demirel, M.C.; Mai, J.; Mendiguren, G.; Koch, J.; Samaniego, L.
; Stisen, S. |
| Quelle | Hydrology and Earth System Sciences |
| Erscheinungsjahr | 2018 |
| Department | CHS |
| Band/Volume | 22 |
| Heft | 2 |
| Seite von | 1299 |
| Seite bis | 1315 |
| Sprache | englisch |
| UFZ Querschnittsthemen | RU5; |
| Abstract | Satellite-based earth observations offer great
opportunities to improve spatial model predictions by means of
spatial-pattern-oriented model evaluations. In this study, observed
spatial patterns of actual evapotranspiration (AET) are utilised for
spatial model calibration tailored to target the pattern performance of
the model. The proposed calibration framework combines temporally
aggregated observed spatial patterns with a new spatial performance
metric and a flexible spatial parameterisation scheme. The mesoscale
hydrologic model (mHM) is used to simulate streamflow and AET and has
been selected due to its soil parameter distribution approach based on
pedo-transfer functions and the build in multi-scale parameter
regionalisation. In addition two new spatial parameter distribution
options have been incorporated in the model in order to increase the
flexibility of root fraction coefficient and potential
evapotranspiration correction parameterisations, based on soil type and
vegetation density. These parameterisations are utilised as they are
most relevant for simulated AET patterns from the hydrologic model. Due
to the fundamental challenges encountered when evaluating spatial
pattern performance using standard metrics, we developed a simple but
highly discriminative spatial metric, i.e. one comprised of three easily
interpretable components measuring co-location, variation and
distribution of the spatial data. The study shows that with flexible spatial model parameterisation used in combination with the appropriate objective functions, the simulated spatial patterns of actual evapotranspiration become substantially more similar to the satellite-based estimates. Overall 26 parameters are identified for calibration through a sequential screening approach based on a combination of streamflow and spatial pattern metrics. The robustness of the calibrations is tested using an ensemble of nine calibrations based on different seed numbers using the shuffled complex evolution optimiser. The calibration results reveal a limited trade-off between streamflow dynamics and spatial patterns illustrating the benefit of combining separate observation types and objective functions. At the same time, the simulated spatial patterns of AET significantly improved when an objective function based on observed AET patterns and a novel spatial performance metric compared to traditional streamflow-only calibration were included. Since the overall water balance is usually a crucial goal in hydrologic modelling, spatial-pattern-oriented optimisation should always be accompanied by traditional discharge measurements. In such a multi-objective framework, the current study promotes the use of a novel bias-insensitive spatial pattern metric, which exploits the key information contained in the observed patterns while allowing the water balance to be informed by discharge observations. |
| dauerhafte UFZ-Verlinkung | https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=19331 |
| Demirel, M.C., Mai, J., Mendiguren, G., Koch, J., Samaniego, L., Stisen, S. (2018): Combining satellite data and appropriate objective functions for improved spatial pattern performance of a distributed hydrologic model Hydrol. Earth Syst. Sci. 22 (2), 1299 - 1315 10.5194/hess-22-1299-2018 |
|