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| Titel |
Exploring the physical controls of regional patterns of flow duration curves – Part 1: Insights from statistical analyses |
| VerfasserIn |
L. Cheng, M. Yaeger, A. Viglione, E. Coopersmith, S. Ye, 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.4435-4446 |
| Datensatznummer |
250013585
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| Publikation (Nr.) |
 copernicus.org/hess-16-4435-2012.pdf |
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| Zusammenfassung |
| The flow duration curve (FDC) is a classical method used
to graphically represent the relationship between the frequency and
magnitude of streamflow. In this sense it represents a compact signature of
temporal runoff variability that can also be used to diagnose catchment
rainfall-runoff responses, including similarity and differences between
catchments. This paper is aimed at extracting regional patterns of the FDCs
from observed daily flow data and elucidating the physical controls
underlying these patterns, as a way to aid towards their regionalization and
predictions in ungauged basins. The FDCs of total runoff (TFDC) using
multi-decadal streamflow records for 197 catchments across the continental
United States are separated into the FDCs of two runoff components, i.e.,
fast flow (FFDC) and slow flow (SFDC). In order to compactly display these
regional patterns, the 3-parameter mixed gamma distribution is employed to
characterize the shapes of the normalized FDCs (i.e., TFDC, FFDC and SFDC)
over the entire data record. This is repeated to also characterize the
between-year variability of "annual" FDCs for 8 representative catchments
chosen across a climate gradient. Results show that the mixed gamma
distribution can adequately capture the shapes of the FDCs and their
variation between catchments and also between years. Comparison between the
between-catchment and between-year variability of the FDCs revealed
significant space-time symmetry. Possible relationships between the
parameters of the fitted mixed gamma distribution and catchment climatic and
physiographic characteristics are explored in order to decipher and point to
the underlying physical controls. The baseflow index (a surrogate for the
collective impact of geology, soils, topography and vegetation, as well as
climate) is found to be the dominant control on the shapes of the normalized
TFDC and SFDC, whereas the product of maximum daily precipitation and the
fraction of non-rainy days was found to control the shape of the FFDC. These
relationships, arising from the separation of total runoff into its two
components, provide a potential physical basis for regionalization of FDCs,
as well as providing a conceptual framework for developing deeper
process-based understanding of the FDCs. |
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