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| Titel |
Exploring the physical controls of regional patterns of flow duration curves – Part 2: Role of seasonality, the regime curve, and associated process controls |
| VerfasserIn |
S. Ye, M. Yaeger, E. Coopersmith, L. Cheng, M. Sivapalan  |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1027-5606
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| Digitales Dokument |
URL |
| Erschienen |
In: Hydrology and Earth System Sciences ; 16, no. 11 ; Nr. 16, no. 11 (2012-11-26), S.4447-4465 |
| Datensatznummer |
250013586
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| Publikation (Nr.) |
 copernicus.org/hess-16-4447-2012.pdf |
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| Zusammenfassung |
| The goal of this paper is to explore the process controls
underpinning regional patterns of variations of streamflow regime behavior,
i.e., the mean seasonal variation of streamflow within the year, across the
continental United States. The ultimate motivation is to use the resulting
process understanding to generate insights into the physical controls of
another signature of streamflow variability, namely the flow duration curve
(FDC). The construction of the FDC removes the time dependence of flows. Thus
in order to better understand the physical controls in regions that exhibit
strong seasonal dependence, the regime curve (RC), which is closely
connected to the FDC, is studied in this paper and later linked back to the
FDC. To achieve these aims a top-down modeling approach is adopted; we start
with a simple two-stage bucket model, which is systematically enhanced
through addition of new processes on the basis of model performance
assessment in relation to observations, using rainfall-runoff data from 197
United States catchments belonging to the MOPEX dataset. Exploration of
dominant processes and the determination of required model complexity are
carried out through model-based sensitivity analyses, guided by a
performance metric. Results indicated systematic regional trends in dominant
processes: snowmelt was a key process control in cold mountainous catchments
in the north and north-west, whereas snowmelt and vegetation cover dynamics
were key controls in the north-east; seasonal vegetation cover dynamics
(phenology and interception) were important along the Appalachian mountain
range in the east. A simple two-bucket model (with no other additions) was
found to be adequate in warm humid catchments along the west coast and in
the south-east, with both regions exhibiting strong seasonality, whereas
much more complex models are needed in the dry south and south-west.
Agricultural catchments in the mid-west were found to be difficult to
predict with the use of simple lumped models, due to the strong influence of
human activities. Overall, these process controls arose from general
east-west (seasonality) and north-south (aridity, temperature) trends in
climate (with some exceptions), compounded by complex dynamics of vegetation
cover and to a less extent by landscape factors (soils, geology and
topography). |
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