FAO-56 Penman-Monteith Daily ETo from Linear Regression Calibrated Hargreaves Equation with Wind Terms in Tropics with Limited Data
Author
Source
International Journal of Agronomy
Issue
Vol. 2014, Issue 2014 (31 Dec. 2014), pp.1-9, 9 p.
Publisher
Hindawi Publishing Corporation
Publication Date
2014-06-02
Country of Publication
Egypt
No. of Pages
9
Main Subjects
Abstract EN
Hargreaves equation (HG), which lacks a wind speed (u2) term, was modified, through a linear regression calibration method, into LHGu which has u2 terms.
LHGu is effectively a simplified method for approximating FAO-56 Penman-Monteith equation (FPM) daily reference evapotranspiration (ETo) in tropics with only temperature data.
In LHGu, the “0.0023” constant term in HG was calibrated as a shifted power function of u2, and the calibration constant was parametrized as a quadratic function of u2.
LHGu was developed using simulated constant u2 data and historical temperature data for four sites in West Africa: Abidjan, Accra, Daloa, and Lome.
LHGu matched FPM ETo better than HG over a wide range of u2: for Accra, for u2 range 0.5–6.0 m/s, the modified coefficient of efficiency, E1, varied narrowly (0.83–0.98) for LHGu but widely (0.14–0.95) for HG optimized for u2=2.0 m/s; the corresponding MBE ranges were −0.05–0.01 mm/d for LHGu and 0.02–0.63 mm/d for HG which cannot respond to varying daily u2.
LHGu is useful for quickly computing practically accurate estimates of FPM ETo for varying daily u2 where only temperature data are available.
American Psychological Association (APA)
Kra, Eric. 2014. FAO-56 Penman-Monteith Daily ETo from Linear Regression Calibrated Hargreaves Equation with Wind Terms in Tropics with Limited Data. International Journal of Agronomy،Vol. 2014, no. 2014, pp.1-9.
https://search.emarefa.net/detail/BIM-469240
Modern Language Association (MLA)
Kra, Eric. FAO-56 Penman-Monteith Daily ETo from Linear Regression Calibrated Hargreaves Equation with Wind Terms in Tropics with Limited Data. International Journal of Agronomy No. 2014 (2014), pp.1-9.
https://search.emarefa.net/detail/BIM-469240
American Medical Association (AMA)
Kra, Eric. FAO-56 Penman-Monteith Daily ETo from Linear Regression Calibrated Hargreaves Equation with Wind Terms in Tropics with Limited Data. International Journal of Agronomy. 2014. Vol. 2014, no. 2014, pp.1-9.
https://search.emarefa.net/detail/BIM-469240
Data Type
Journal Articles
Language
English
Notes
Includes bibliographical references
Record ID
BIM-469240