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| Titel |
Climate-vegetation-soil interactions and long-term hydrologic partitioning: signatures of catchment co-evolution |
| VerfasserIn |
P. A. Troch, G. Carrillo, M. Sivapalan  , T. Wagener, K. Sawicz |
| 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 ; 17, no. 6 ; Nr. 17, no. 6 (2013-06-18), S.2209-2217 |
| Datensatznummer |
250018900
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| Publikation (Nr.) |
 copernicus.org/hess-17-2209-2013.pdf |
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| Zusammenfassung |
| Budyko (1974) postulated that long-term catchment water
balance is controlled to first order by the available water and energy. This
leads to the interesting question of how do landscape characteristics
(soils, geology, vegetation) and climate properties (precipitation,
potential evaporation, number of wet and dry days) interact at the catchment
scale to produce such a simple and predictable outcome of hydrological
partitioning? Here we use a physically-based hydrologic model separately
parameterized in 12 US catchments across a climate gradient to decouple the
impact of climate and landscape properties to gain insight into the role of
climate-vegetation-soil interactions in long-term hydrologic partitioning.
The 12 catchment models (with different paramterizations) are subjected to
the 12 different climate forcings, resulting in 144 10 yr model
simulations. The results are analyzed per catchment (one catchment model
subjected to 12 climates) and per climate (one climate filtered by 12
different model parameterization), and compared to water balance predictions
based on Budyko's hypothesis (E/P = ϕ (Ep/P); E: evaporation,
P: precipitation, Ep: potential evaporation). We find significant
anti-correlation between average deviations of the evaporation index (E/P)
computed per catchment vs. per climate, compared to that predicted by
Budyko. Catchments that on average produce more E/P have developed in
climates that on average produce less E/P, when compared to Budyko's
prediction. Water and energy seasonality could not explain these
observations, confirming previous results reported by Potter et al. (2005).
Next, we analyze which model (i.e., landscape filter) characteristics
explain the catchment's tendency to produce more or less E/P. We find that
the time scale that controls subsurface storage release explains the
observed trend. This time scale combines several geomorphologic and
hydraulic soil properties. Catchments with relatively longer subsurface
storage release time scales produce significantly more E/P. Vegetation in
these catchments have longer access to this additional groundwater source
and thus are less prone to water stress. Further analysis reveals that
climates that give rise to more (less) E/P are associated with catchments
that have vegetation with less (more) efficient water use parameters. In
particular, the climates with tendency to produce more E/P have catchments
that have lower % root fraction and less light use efficiency. Our
results suggest that their exists strong interactions between climate,
vegetation and soil properties that lead to specific hydrologic partitioning
at the catchment scale. This co-evolution of catchment vegetation and soils
with climate needs to be further explored to improve our capabilities to
predict hydrologic partitioning in ungauged basins. |
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