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Titre du document / Document title

History and evaluation of Hargreaves evapotranspiration equation

Auteur(s) / Author(s)

HARGREAVES George H. (1) ; ALLEN Richard G. (2) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) International Irrigation Center, Dept. of Biological and Irrigation Engineering, Utah State Univ., Logan, UT 84322-4150, ETATS-UNIS
(2) Univ. of Idaho Research and Extension Center, Kimberly, ID 83341, ETATS-UNIS

Résumé / Abstract

A brief history of development of the 1985 Hargreaves equation and its comparison to evapotranspiration (ET) predicted by the Food and Agricultural Organization of the United Nations (FAO) Penman-Monteith method are described to provide background and information helpful in selecting an appropriate reference ET equation under various data situations. Early efforts in irrigation water requirement computations in California and other arid and semiarid regions required the development of simplified ET equations for use with limited weather data. Several initial efforts were directed towards improving the usefulness of pan evaporation for estimating irrigation water requirements. Similarity with climates of other countries allowed developments in California to be extended overseas. Criticism of empirical methods by H. L. Penman and others encouraged the search for a robust and practical method that was based on readily available climatic data for computing potential evapotranspiration or reference crop evapotranspiration (ET0). One of these efforts ultimately culminated in the 1985 Hargreaves ET0 method. The 1985 Hargreaves ET0 method requires only measured temperature data, is simple, and appears to be less impacted than Penman-type methods when data are collected from arid or semiarid, nonirrigated sites. For irrigated sites, the Hargreaves 1985 ET0 method produces values for periods of five or more days that compare favorably with those of the FAO Penman-Monteith and California Irrigation Management Information Services (CIMIS) Penman methods. The Hargreaves ET0 predicted 0.97 of lysimeter measured ET0 at Kimberly, Idaho after adjustment of lysimeter data for differences in surface conductance from the FAO Penman-Monteith definition. Monthly ET0 by the 1985 Hargreaves equation compares closely with ET0 calculated using a simplified, reduced-set Penman-Monteith that requires air temperature data only.

Revue / Journal Title

Journal of irrigation and drainage engineering    ISSN  0733-9437   CODEN JIDEDH 

Source / Source

2003, vol. 129, no1, pp. 53-63 [11 page(s) (article)] (1 p.1/4)

Langue / Language

Anglais

Editeur / Publisher

American Society of Civil Engineers, Reston, VA, ETATS-UNIS  (1983) (Revue)

Mots-clés anglais / English Keywords

Agroclimatology

;

America

;

North America

;

United States

;

Arid environment

;

California

;

Thermal factor

;

Regression equation

;

Water requirement

;

Evapotranspiration

;

Mots-clés français / French Keywords

Agroclimatologie

;

Amérique

;

Amérique du Nord

;

Etats Unis

;

Milieu aride

;

Californie

;

Facteur thermique

;

Equation régression

;

Besoin hydrique

;

Evapotranspiration

;

Mots-clés espagnols / Spanish Keywords

Agroclimatología

;

America

;

America del norte

;

Estados Unidos

;

Medio árido

;

California

;

Factor térmico

;

Ecuación regresión

;

Necesidad hidráulica

;

Evapotranspiración

;

Mots-clés d'auteur / Author Keywords

Evapotranspiration

;

History

;

California

;

Arid lands

;

Localisation / Location

INIST-CNRS, Cote INIST : 572 H, 35400010377886.0070

Nº notice refdoc (ud4) : 14469542



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