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Titel |
Improving the complementary methods to estimate evapotranspiration under diverse climatic and physical conditions |
VerfasserIn |
F. M. Anayah, J. J. Kaluarachchi |
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 ; 18, no. 6 ; Nr. 18, no. 6 (2014-06-03), S.2049-2064 |
Datensatznummer |
250120374
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Publikation (Nr.) |
copernicus.org/hess-18-2049-2014.pdf |
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Zusammenfassung |
Reliable estimation of evapotranspiration (ET) is important for the purpose
of water resources planning and management. Complementary methods, including
complementary relationship areal evapotranspiration (CRAE),
advection aridity (AA) and Granger and Gray (GG), have been used to estimate
ET because these methods are simple and practical in estimating regional ET
using meteorological data only. However, prior studies have found
limitations in these methods especially in contrasting climates. This study
aims to develop a calibration-free universal method using the complementary
relationships to compute regional ET in contrasting climatic and physical
conditions with meteorological data only. The proposed methodology consists
of a systematic sensitivity analysis using the existing complementary
methods. This work used 34 global FLUXNET sites where eddy covariance (EC)
fluxes of ET are available for validation. A total of 33 alternative model
variations from the original complementary methods were proposed. Further
analysis using statistical methods and simplified climatic class definitions
produced one distinctly improved GG-model-based alternative. The proposed
model produced a single-step ET formulation with results equal to or better
than the recent studies using data-intensive, classical methods. Average
root mean square error (RMSE), mean absolute bias (BIAS) and R2 (coefficient of determination) across
34 global sites were 20.57 mm month−1, 10.55 mm month−1 and 0.64, respectively.
The proposed model showed a step forward toward predicting ET in large river
basins with limited data and requiring no calibration. |
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