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| Titel |
A model for hydraulic redistribution incorporating coupled soil-root moisture transport |
| VerfasserIn |
G. G. Amenu, P. Kumar |
| 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 ; 12, no. 1 ; Nr. 12, no. 1 (2008-01-24), S.55-74 |
| Datensatznummer |
250010458
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| Publikation (Nr.) |
 copernicus.org/hess-12-55-2008.pdf |
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| Zusammenfassung |
| One of the adaptive strategies of vegetation, particularly in water limited
ecosystems, is the development of deep roots and the use of hydraulic
redistribution which enables them to make optimal use of resources available
throughout the soil column. Hydraulic redistribution refers to roots acting
as a preferential pathway for the movement of water from wet to dry soil
layers driven by the moisture gradient – be it from the shallow to deep
layers or vice versa. This occurs during the nighttime while during the
daytime moisture movement is driven to fulfill the transpiration demand at
the canopy. In this study, we develop a model to investigate the effect of
hydraulic redistribution by deep roots on the terrestrial climatology.
Sierra Nevada eco-region is chosen as the study site which has wet winters
and dry summers. Hydraulic redistribution enables the movement of moisture
from the upper soil layers to deeper zones during the wet months and this
moisture is then available to meet the transpiration demand during the late
dry season. It results in significant alteration of the profiles of soil
moisture and water uptake as well as increase in the canopy transpiration,
carbon assimilation, and the associated water-use-efficiency during the dry
summer season. This also makes the presence of roots in deeper soil layers
much more important than their proportional abundance would otherwise
dictate. Comparison with observations of latent heat from a flux tower
demonstrates improved predictability and provides validation of the model
results. Hydraulic redistribution serves as a mechanism for the interaction
between the variability of deep layer soil-moisture and the land-surface
climatology and could have significant implications for seasonal and
sub-seasonal climate prediction. |
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