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Adequacy of selected evapotranspiration approximations for hydrologic simulation

Journal of the American Water Resources Association

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DOI: 10.1111/j.1752-1688.2006.tb04486.x

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Abstract

Evapotranspiration (ET) approximations, usually based on computed potential ET (PET) and diverse PET-to-ET conceptualizations, are routinely used in hydrologic analyses. This study presents an approach to incorporate measured (actual) ET data, increasingly available using micrometeorological methods, to define the adequacy of ET approximations for hydrologic simulation. The approach is demonstrated at a site where eddy correlation-measured ET values were available. A baseline hydrologic model incorporating measured ET values was used to evaluate the sensitivity of simulated water levels, subsurface recharge, and surface runoff to error in four ET approximations. An annually invariant pattern of mean monthly vegetation coefficients was shown to be most effective, despite the substantial year-to-year variation in measured vegetation coefficients. The temporal variability of available water (precipitation minus ET) at the humid, subtropical site was largely controlled by the relatively high temporal variability of precipitation, benefiting the effectiveness of coarse ET approximations, a result that is likely to prevail at other humid sites.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Adequacy of selected evapotranspiration approximations for hydrologic simulation
Series title:
Journal of the American Water Resources Association
DOI:
10.1111/j.1752-1688.2006.tb04486.x
Volume
42
Issue:
3
Year Published:
2006
Language:
English
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Journal of the American Water Resources Association
First page:
699
Last page:
711