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| Titel |
Subsurface storage capacity influences climate–evapotranspiration interactions in three western United States catchments |
| VerfasserIn |
E. S. Garcia, C. L. Tague |
| 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 ; 19, no. 12 ; Nr. 19, no. 12 (2015-12-18), S.4845-4858 |
| Datensatznummer |
250120867
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| Publikation (Nr.) |
 copernicus.org/hess-19-4845-2015.pdf |
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| Zusammenfassung |
| In the winter-wet, summer-dry forests of the western United States, total
annual evapotranspiration (ET) varies with precipitation and temperature.
Geologically mediated drainage and storage properties, however, may strongly
influence these relationships between climate and ET. We use a physically
based process model to evaluate how plant accessible water storage capacity
(AWC) and rates of drainage influence model estimates of ET–climate
relationships for three snow-dominated, mountainous catchments with differing
precipitation regimes. Model estimates show that total annual precipitation
is a primary control on inter-annual variation in ET across all catchments
and that the timing of recharge is a second-order control. Low AWC, however,
increases the sensitivity of annual ET to these climate drivers by 3 to 5
times in our two study basins with drier summers. ET–climate relationships
in our Colorado basin receiving summer precipitation are more stable across
subsurface drainage and storage characteristics. Climate driver–ET
relationships are most sensitive to subsurface storage (AWC) and drainage
parameters related to lateral redistribution in the relatively dry Sierra
site that receives little summer precipitation. Our results demonstrate that
uncertainty in geophysically mediated storage and drainage properties can
strongly influence model estimates of watershed-scale ET responses to climate
variation and climate change. This sensitivity to uncertainty in geophysical
properties is particularly true for sites receiving little summer
precipitation. A parallel interpretation of this parameter sensitivity is
that spatial variation in storage and drainage properties are likely to lead
to substantial within-watershed plot-scale differences in forest water use
and drought stress. |
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