Reference Evapotranspiration Estimation in Tropical Region using Penman-Monteith Equation and Evolutionary Computation

Author(s):  
Saiful Farhan Mohd Samsuri ◽  
Robiah Ahmad ◽  
Mohd Zakimi Zakaria
2021 ◽  
Author(s):  
Rouhin Mitra ◽  
Mekonnen Gebremichael ◽  
Isabel Franco Trigo ◽  
Henk A.R. de Bruin

<p>Reference evapotranspiration (ETo), a hypothetical concept to estimate evapotranspiration from irrigated and large grass fields is crucial in finding the irrigation water demand in places with extensive agricultural practice. In general, the FAO method (based on the Penman-Monteith equation) is used to estimate ETo from stations that are placed in locations that violate the requirements for reference evapotranspiration. In this study we compare radiation-based methods used to estimate reference evapotranspiration such as ETo De Bruin and ETo Makkink with more conventional ETo approaches in FAO PM method and Priestley Taylor method using in-situ measurements from stations placed in two different settings: (1) Areas that are well-irrigated but surrounded by dry land, (2) Areas that are dry but extensive. We use two spatially dense networks of stations: 1) CIMIS stations of California located in irrigated and in-extensive fields, (2) MESONET stations of Oklahoma located on dry surfaces.  We analyze the differences in the ETo estimates and hypothesize that the radiation-based estimates give more accurate results in the conditions given above for irrigation advisory. We also assess the spatial variability of the different ETo estimates and attempt to investigate the reason behind the differences in these estimates due to the climatic factors.</p>


Author(s):  
Gustavo H. da Silva ◽  
Santos H. B. Dias ◽  
Lucas B. Ferreira ◽  
Jannaylton É. O. Santos ◽  
Fernando F. da Cunha

ABSTRACT FAO Penman-Monteith (FO-PM) is considered the standard method for the estimation of reference evapotranspiration (ET0) but requires various meteorological data, which are often not available. The objective of this work was to evaluate the performance of the FAO-PM method with limited meteorological data and other methods as alternatives to estimate ET0 in Jaíba-MG. The study used daily meteorological data from 2007 to 2016 of the National Institute of Meteorology’s station. Daily ET0 values were randomized, and 70% of these were used to determine the calibration parameters of the ET0 for the equations of each method under study. The remaining data were used to test the calibration against the standard method. Performance evaluation was based on Willmott’s index of agreement, confidence coefficient and root-mean-square error. When one meteorological variable was missing, either solar radiation, relative air humidity or wind speed, or in the simultaneous absence of wind speed and relative air humidity, the FAO-PM method showed the best performances and, therefore, was recommended for Jaíba. The FAO-PM method with two missing variables, one of them being solar radiation, showed intermediate performance. Methods that used only air temperature data are not recommended for the region.


Irriga ◽  
2018 ◽  
Vol 21 (2) ◽  
pp. 269 ◽  
Author(s):  
Vágna Da Costa Pereira ◽  
Gilberto Chohaku Sediyama ◽  
Magna Soelma Beserra De Moura ◽  
Thieres George Freire Da Silva ◽  
Luciana Sandra Bastos De Souza

EFICIÊNCIA DO USO DA ÁGUA EM VIDEIRA ‘SYRAH’ IRRIGADA NO SUBMÉDIO DO VALE SÃO FRANCISCO1 VÁGNA DA COSTA PEREIRA1; GILBERTO CHOHAKU SEDIYAMA2; MAGNA SOELMA BESERRA DE MOURA3; THIERES GEORGE FREIRE DA SILVA4 E LUCIANA SANDRA BASTOS DE SOUZA51Resultado da Dissertação de Mestrado do primeiro autor2Doutoranda em Meteorologia Agrícola – Departamento de Engenharia Agrícola – Universidade Federal de Viçosa – Campus Viçosa – 36570-900 – Viçosa, Minas Gerais, Brasil, [email protected]. Titular – Departamento de Engenharia Agrícola – Universidade Federal de Viçosa – Campus Viçosa – 36570-900 – Viçosa, Minas Gerais, Brasil, [email protected] – Núcleo Temático de Recursos Naturais – Embrapa Semiárido – 56302-970 – Petrolina, Pernambuco, Brasil, [email protected]. Adjunto – Departamento de Ciências Agrárias – Universidade Federal Rural de Pernambuco – Unidade Acadêmica de Serra Talhada – 56909-535 – Serra Talhada, Pernambuco, Brasil, [email protected]. Assistente – Departamento de Ciências Agrárias – Universidade Federal Rural de Pernambuco – Unidade Acadêmica de Serra Talhada – 56909-535 – Serra Talhada, Pernambuco, Brasil, [email protected]  1 RESUMO O estudo teve como objetivo estimar a eficiência do uso da água (EUA) na videira ‘Syrah’ irrigada no Submédio do Vale São Francisco, com base no rendimento em função da evapotranspiração da cultura e da transpiração máxima. Para isso, a evapotranspiração da cultura foi determinada pelo balanço de energia com base no método da razão de Bowen (ETcBERB), enquanto a transpiração máxima (TR) foi estimada pelo modelo de Penman-Monteith modificado com base no índice de área foliar da cultura. Os dados micrometeorológicos foram monitorados durante um ciclo produtivo por meio de uma estação automática localizada no parreiral. A evapotranspiração de referência (ETo) também foi calculada ao longo do experimento, pelo método de Penman-Monteith parametrizado no boletim 56 da FAO. A ETo e a ETcBERB corresponderam ao valor total de 474,0 e 376,4 mm ciclo-1, com valor médio diário de 3,9 e 3,1 mm, respectivamente. A TR oscilou entre 3,5 e 0,9 mm d-1, com volume total durante o ciclo de 284,4 mm. A EUA, com base no total de água consumida e transpirada, foi de 1,17 kg m-3 e 1,55 kg m-3, respectivamente. O método do BERB e o modelo de Penman-Monteith modificado para plantas isoladas apresentaram resultados confiáveis para estimativa da EUA sob as condições climáticas da região do Submédio do Vale São Francisco. No entanto, torna-se necessário que novos estudos nesse sentido com a cultura da videira para produção de vinhos sejam realizados, principalmente nesta região Semiárida, onde a maioria das pesquisas voltadas para o manejo do vinhedo ainda estão em desenvolvimento. Palavras-chave: semiárido, evapotranspiração, razão de Bowen, transpiração máxima   PEREIRA, V. C.; SEDIYAMA, G. C.; MOURA, M. S. B.; SILVA, T. G. F.; SOUZA, L. S. B.WATER USE EFFICIENCY IN IRRIGATED "SYRAH'' GRAPE PLANTATION AT SÃO FRANCISCO RIVER VALLEY  2 ABSTRACT The objective of this work was to evaluate the water use efficiency (WUE) in  irrigated ‘Syrah’ grapevine plantation at São Francisco River valley, on the basis of yields as a function of crop evapotranspiration and maximum transpiration. To this end, the crop evapotranspiration was determined by energy balance based on the Bowen ratio method (ETcBERB), while the maximum transpiration (TR) was estimated by the modified Penman-Monteith equation based on the crop leaf area index. The micrometeorological data within the vineyard canopy were monitored using an automatic micrometeorological station, during a productive cycle. The reference evapotranspiration (ETo) was also calculated during that period using the FAO parameterized Penman-Monteith equation. The reference evapotranspiration (ETo) and the crop evapotranspiration determined by BREB method (ETcBERB), during the crop cycle, were 474.0 and 376.4 mm cycle-1, respectively, with a daily average of 3.9 and 3.1 mm. The TR rate ranged between 3.5 and 0.9 mm d-1, with total volume during 284.4 mm cycle -1. The WUE, on the basis of the total water consumed and transpiration, was 1.17 kg m-3 and 1.55 kg m-3, respectively. The BERB method and the Penman-Monteith model modified to isolated plants showed reliable results to estimate the WUE under the climatic conditions of São Francisco River valley. However, new studies on grape culture for wine production are necessary, especially in this semiarid region, where most researches focused on the vineyard management are still in development. Keywords: Bowen ratio. Evapotranspiration. Maximum transpiration. Semiarid. 


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