Reference evapotranspiration estimates by means of Hargreaves-samani and Penman-monteith fao methods with missing data in the northwestern Mato Grosso do Sul

Fernando França Da Cunha,Flávio Bastos Campos,Luan Peroni Venancio,Gilberto Chohaku Sediyama

doi:10.14393/bj-v33n5a2017-36751

Abstract

Reference evapotranspiration estimates by means of Hargreaves-samani and Penman-monteith fao methods with missing data in the northwestern Mato Grosso do Sul

Highlights

The reference evapotranspiration (ET0) is widely used for irrigation engineering to define the crop water needs and to manage the water distribution in existing systems (DROOGERS; ALLEN; 2002).The Penman-Monteith FAO method (PMFAO) is widely used to estimate ET0
The objective of this paper was to evaluate the performance of the Penman-Monteith (PMFAO) with missing data and Hargreaves-Samani methods to estimate the ET0, for five locations in the Northwestern region of Mato Grosso do Sul
High coefficients of determination were observed (r2 > 0.92), regardless the season, when estimating ET0 for missing relative air humidity and wind speed data. This result is attributed to the average value that satisfactorily represented the wind speed in each annual season, due to the low temporal variability presented by this factor; and due to a good correlation between dew point humidity and minimum humidity, which was used to estimate the air relative humidity

Summary

Introduction

The reference evapotranspiration (ET0) is widely used for irrigation engineering to define the crop water needs and to manage the water distribution in existing systems (DROOGERS; ALLEN; 2002).The Penman-Monteith FAO method (PMFAO) is widely used to estimate ET0. In order to find alternatives when facing this situation, many researchers have been proposed estimating ET0 with methods that demand less input data (ALENCAR et al, 2011; FANAYA JUNIOR et al, 2012; CHAGAS et al, 2013; PALARETTI et al, 2014; CARVALHO et al, 2015). Among those methods, Hargreaves-Samani (HARGREAVES; SAMANI, 1985), with only minimum and maximum temperature data, is considered the simplest one to estimate the reference evapotranspiration (ALENCAR et al, 2015) and it can be used for irrigation management (NÓIA et al, 2014)

Objectives

Methods

Results