Estimation of the potential evapotranspiration by a simplified penman method

Engenharia Agrícola

Nilson A. Villa Nova²  Jarbas H. De Miranda¹  André B. Pereira¹  Késia O. Da Silva¹ 

[1] ,USP Escola Superior de Agricultura 'Luiz de Queiroz' Departamento de Ciências ExatasPiracicaba SP

关键词: crop water use;    Bowen ratio;    energy balance;    consumo hídrico;    razão de Bowen;    balanço de energia;   

DOI  :  10.1590/S0100-69162006000300007

来源: SciELO

【 摘 要 】

The numerous methods for calculating the potential or reference evapotranspiration (ETo or ETP) almost always do for a 24-hour period, including values of climatic parameters throughout the nocturnal period (daily averages). These results have a nil effect on transpiration, constituting the main evaporative demand process in cases of localized irrigation. The aim of the current manuscript was to come up with a model rather simplified for the calculation of diurnal daily ETo. It deals with an alternative approach based on the theoretical background of the Penman method without having to consider values of aerodynamic conductance of latent and sensible heat fluxes, as well as data of wind speed and relative humidity of the air. The comparison between the diurnal values of ETo measured in weighing lysimeters with elevated precision and estimated by either the Penman-Monteith method or the Simplified-Penman approach in study also points out a fairly consistent agreement among the potential demand calculation criteria. The Simplified-Penman approach was a feasible alternative to estimate ETo under the local meteorological conditions of two field trials. With the availability of the input data required, such a method could be employed in other climatic regions for scheduling irrigation.

【 授权许可】

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