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Performance of SAFER evapotranspiration using missing meteorological data

2020; Elsevier BV; Volume: 233; Linguagem: Inglês

10.1016/j.agwat.2020.106076

1873-2283

Jannaylton Éverton Oliveira Santos, Fernando França da Cunha, Roberto Filgueiras, Gustavo Henrique da Silva, A. H. de C. Teixeira, Francisco Charles dos Santos Silva, Gilberto Chohaku Sediyama,

Irrigation Practices and Water Management

The Simple Algorithm for Evapotranspiration Retrieving (SAFER) can be used to estimate surface evapotranspiration. In the process of SAFER parameterization, the reference evapotranspiration (ETo) calculated by the Penman-Monteith (PM) method was included. However, methodologies for estimating ETo that use fewer meteorological variables should be sought, mainly to increase the applicability of the method in regions where there are no complete weather stations. Thus, the objective of this study was to evaluate the impact of the ETo calculated with estimated data on the calculation of surface evapotranspiration using SAFER (ETSAFER) in the Brazilian semiarid region. The study was carried out in areas of centre pivots cultivated with sugarcane located in the public irrigated perimeter of Jaíba, MG, Brazil. ETo and its impact on ETSAFER were analysed using meteorological data from a station belonging to the National Institute of Meteorology (INMET) as well as data from 19 images of the Landsat 8 satellite from 2013, 2014 and 2016. The ETSAFER responses were analysed from the calculations of ETo estimated by the Hargreaves-Samani (HS) and PM methods with missing data including single absences of solar radiation (RS), wind speed (U2), relative humidity (RH) and combined absences of U2 and RH, U2, RH and RS, RS and U2, and RS and RH. The temporal and spatial variability of ETSAFER for sugarcane crops was assessed. RS was the parameter that most affected ETo and, consequently, ETSAFER. ETSAFER was underestimated when calculated using the ETo estimated by PM with missing RS data and overestimated when the ETo was calculated by HS. In the absence of single or combined data of U2 and RH, it is recommended to estimate ETo by PM with missing data for the calculation of ETSAFER. It is not advised to use the ETo obtained by the HS method for calculating ETSAFER in semiarid regions.