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Titel |
Does model performance improve with complexity? A case study with three hydrological models |
VerfasserIn |
Rene Orth, Maria Staudinger, Sonia I. Seneviratne, Jan Seibert, Massimiliano Zappa |
Konferenz |
EGU General Assembly 2015
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Medientyp |
Artikel
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Sprache |
Englisch
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 17 (2015) |
Datensatznummer |
250108878
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Publikation (Nr.) |
EGU/EGU2015-8714.pdf |
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Zusammenfassung |
In recent decades considerable progress has been made in climate model development.
Following the massive increase in computational power, models became more sophisti-
cated. At the same time also simple conceptual models have advanced. In this study we
validate and compare three hydrological models of different complexity to investigate
whether their performance varies accordingly. For this purpose we use runoff and also
soil moisture measurements, which allow a truly independent validation, from several
sites across Switzerland. The models are calibrated in similar ways with the same runoff
data. Our results show that the more complex models HBV and PREVAH outperform
the simple water balance model (SWBM) in case of runoff but not for soil moisture.
Furthermore the most sophisticated PREVAH model shows an added value compared
to the HBV model only in case of soil moisture. Focusing on extreme events we find
generally improved performance of the SWBM during drought conditions and degraded
agreement with observations during wet extremes. For the more complex models we
find the opposite behavior, probably because they were primarily developed for predic-
tion of runoff extremes. As expected given their complexity, HBV and PREVAH have
more problems with over-fitting. All models show a tendency towards better perfor-
mance in lower altitudes as opposed to (pre-)alpine sites. The results vary considerably
across the investigated sites. In contrast, the different metrics we consider to estimate
the agreement between models and observations lead to similar conclusions, indicating
that the performance of the considered models is similar at different time scales as well
as for anomalies and long-term means. We conclude that added complexity does not
necessarily lead to improved performance of hydrological models, and that performance
can vary greatly depending on the considered hydrological variable (e.g. runoff vs. soil
moisture) or hydrological conditions (floods vs. droughts). |
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