Comparison of meteorological data, related to reference evapotranspiration, from conventional and automatic stations in the Sertão and Agreste regions of Pernambuco, Brazil

The objective was to perform a comparative study of the meteorological elements data that most cause changes in the reference Evapotranspiration (ETo, mm) and its own value, of automatic weather stations AWS and conventional weather stations CWS of the Sertão and Agreste regions of Pernambuco State. The ETo was calculated on a daily scale using the standard method proposed by the Food and Agriculture Organization (FAO), Penman-Monteith (FAO-56). The ETo information obtained from AWS data can be used to update the weather database of stations, since there is a good relationship between the ETo data obtained from CWS and AWS, statistically determined by the Willmott's concordance index (d > 0.7). The observed variations in the weather elements: air temperature, relative humidity, wind speed, and global solar radiation have not caused significant changes in the ETo calculation.

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Combination of satellite imagery with meteorological data for estimating reference evapotranspiration

Revista de Teledetección ◽

10.4995/raet.2018.7688 ◽

2018 ◽

pp. 75

Author(s):

D. Montero ◽

F. Echeverry ◽

F. Hernández

Keyword(s):

Land Surface Temperature ◽

Land Surface ◽

Reference Evapotranspiration ◽

Meteorological Data ◽

Meteorological Station ◽

Significant Relation ◽

Food And Agriculture ◽

Food And Agriculture Organization ◽

Digital Elevation ◽

Weather Stations

<p>The Food and Agriculture Organization of the United Nations (FAO) in its publication No. 56 of the Irrigation and Drainage Series presents the FAO Penman-Monteith procedure for the estimation of reference evapotranspiration from meteorological data, however, its calculation may be complicated in areas where there are no weather stations. This paper presents an evaluation of the potential of the Land Surface Temperature and Digital Elevation Models products derived from the MODIS and ASTER sensors, both on board the Terra EOS AM-1 satellite, for the estimation of reference evapotranspiration using the Penman-Monteith FAO-56, Hargreaves, Thornthwaite and Blaney-Criddle models. The four models were compared with the method proposed by FAO calculated with the observed data of a ground based meteorological station, finding a significant relation with the models Penman-Monteith FAO-56 and Hargreaves.</p>

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Optimal Selection of Empirical Reference Evapotranspiration Method in 36 Different Agricultural Zones of China

Agronomy ◽

10.3390/agronomy12010031 ◽

2021 ◽

Vol 12 (1) ◽

pp. 31

Author(s):

Yong Yang ◽

Rensheng Chen ◽

Chuntan Han ◽

Zhangwen Liu ◽

Xiqiang Wang

Keyword(s):

Reference Evapotranspiration ◽

Meteorological Data ◽

Aridity Index ◽

Empirical Method ◽

Climatic Conditions ◽

Food And Agriculture ◽

Food And Agriculture Organization ◽

Temperature Method ◽

The Relationship ◽

Selection Of

The Food and Agriculture Organization has proposed the current version of the Penman–Monteith method (FAO56-PM) as the standard for calculating reference evapotranspiration (ET0); however, high meteorological data requirements limit its application in many areas. There is thus an urgent need to identify the best alternative empirical method to accurately calculate ET0 in regions that lack sufficient meteorological data. In this study, three temperature-based methods and five radiation-based methods were evaluated using ET0 values generated using the FAO56-PM method in 36 agricultural zones in China based on meteorological data from 823 stations, measured between 2011 and 2020. The results showed that the optimal temperature-based method and radiation-based method differed for different agricultural zones, and no one temperature method or radiation method could be suitable for all agricultural zones. The eight empirical methods were regionally calibrated to improve the ET0 calculation accuracy in the different zones. The relationship between the optimal methods and climatic conditions showed that the most reliable empirical method could be selected according to the local annual mean temperature and aridity index. The results provide useful guidance for the selection of reliable empirical ET0 methods in agricultural zones outside China.

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Estimation methods of reference evapotranspiration (ETo) for Uberlândia -MG

Engenharia Agrícola ◽

10.1590/1809-4430-eng.agric.v35n1p27-38/2015 ◽

2015 ◽

Vol 35 (1) ◽

pp. 27-38 ◽

Cited By ~ 4

Author(s):

ZILDA C. DE LACERDA ◽

JOSÉ E. P. TURCO

Keyword(s):

Solar Radiation ◽

Reference Evapotranspiration ◽

Global Solar Radiation ◽

Daily Basis ◽

Meteorological Station ◽

Estimation Methods ◽

Food And Agriculture ◽

Food And Agriculture Organization ◽

Daily Data ◽

Analysis Of Results

One approach to verify the adequacy of estimation methods of reference evapotranspiration is the comparison with the Penman-Monteith method, recommended by the United Nations of Food and Agriculture Organization - FAO, as the standard method for estimating ET0. This study aimed to compare methods for estimating ET0, Makkink (MK), Hargreaves (HG) and Solar Radiation (RS), with Penman-Monteith (PM). For this purpose, we used daily data of global solar radiation, air temperature, relative humidity and wind speed for the year 2010, obtained through the automatic meteorological station, with latitude 18° 91' 66" S, longitude 48° 25' 05" W and altitude of 869m, at the National Institute of Meteorology situated in the Campus of Federal University of Uberlandia - MG, Brazil. Analysis of results for the period were carried out in daily basis, using regression analysis and considering the linear model y = ax, where the dependent variable was the method of Penman-Monteith and the independent, the estimation of ET0 by evaluated methods. Methodology was used to check the influence of standard deviation of daily ET0 in comparison of methods. The evaluation indicated that methods of Solar Radiation and Penman-Monteith cannot be compared, yet the method of Hargreaves indicates the most efficient adjustment to estimate ETo.

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Performance evaluation of artificial neural networks in estimating reference evapotranspiration with minimal meteorological data

Global NEST Journal ◽

10.30955/gnj.000758 ◽

2013 ◽

Vol 13 (1) ◽

pp. 18-27

Keyword(s):

Reference Evapotranspiration ◽

Meteorological Data ◽

Learning Rule ◽

Food And Agriculture ◽

Air Temperatures ◽

Food And Agriculture Organization ◽

Cascade Correlation ◽

Ann Models ◽

Artificial Neural ◽

Artificial Neural Network Ann

Detailed meteorological data required for the equation of FAO-56 Penman-Monteith (P-M) method that was adopted by Food and Agriculture Organization (FAO) as a standard method in estimating reference evapotranspiration (ETo) are not often available, especially in developing countries. The Hargreaves equation (HG) has been successfully used in some locations to estimate ETo where sufficient data were not available to use the P-M method. This paper investigates the potential of two Artificial Neural Network (ANN) architectures, the multilayer perceptron architecture, in which a backpropagation algorithm (BPANN) is used, and the cascade correlation architecture (CCANN), in which Kalman’s learning rule is embedded in modeling the daily ETo with minimal meteorological data. An overview of the features of ANNs and traditional methods such as P-M and HG is presented, and the advantages and limitations of each method are discussed. Daily meteorological data from three automatic weather stations located in Greece were used to optimize and test the different models. The exponent value of the HG equation was locally optimized, and an adjusted HGadj equation was used. The comparisons were based on error statistical techniques using P-M daily ETo values as reference. According to the results obtained, it was found that taking into account only the mean, maximum and minimum air temperatures, the selected ANN models markedly improved the daily ETo estimates and provided unbiased predictions and systematically better accuracy compared with the HGadj equation. The results also show that the CCANN model performed better than the BPANN model at all stations.

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CALIBRATION OF THE HARGREAVES-SAMANI EQUATION FOR SPECIFIC PERIODS OF THE YEAR IN THE MUNICIPALITY OF JAÍBA-MG, BRAZIL

Revista Engenharia na Agricultura - REVENG ◽

10.13083/reveng.v25i5.838 ◽

2017 ◽

Vol 25 (5) ◽

pp. 445-453

Author(s):

Anunciene Barbosa Duarte ◽

Lucas Borges Ferreira ◽

Edson Fagne Dos Santos

Keyword(s):

Reference Evapotranspiration ◽

Meteorological Data ◽

Climatic Conditions ◽

Crop Water ◽

Climatic Effects ◽

Food And Agriculture ◽

Food And Agriculture Organization ◽

Crop Water Demand ◽

Limited Application ◽

Monteith Equation

Reference evapotranspiration (ET0) explains the climatic effects on crop water demand. The Food and Agriculture Organization (FAO) recommends the Penman Monteith equation as a standard method for estimating ET0. However, because this equation requires a large amount of meteorological data, it has limited application. An alternative is the Hargreaves-Samani (HS) equation, which only requires air temperature data, and can be calibrated to specifc locations and periods. The present study aimed to calibrate the empirical parameters (coeffcients and exponent) of the HS equation for specifc periods of the year, as well as evaluate the behavior and calibration of this equation throughout the year in the municipality of Jaíba-MG, Brazil. The daily meteorological data from 1996 to 2011 were gathered from a weather station located in the municipality of Jaíba-MG. A general calibration was performed per semester, per season, per month, and during periods with similar climatic conditions. The calibration of the HS equation, in all of the forms studied, promoted better ET0estimations. The calibrations for specifc periods of the year only promoted slight increases in performance in relation to the general calibration, therefore they, in general, presented equal performance to each other.

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Empirical Equations to Estimate Evapotranspiration in Mosul City

Tikrit Journal of Engineering Sciences ◽

10.25130/tjes.27.4.10 ◽

2020 ◽

Vol 27 (4) ◽

pp. 98-102

Author(s):

Haqqi Yasin ◽

Luma Abdullah

Keyword(s):

Wind Speed ◽

Relative Humidity ◽

Air Temperature ◽

Reference Evapotranspiration ◽

Sunshine Duration ◽

Food And Agriculture ◽

Food And Agriculture Organization ◽

Daily Data ◽

Daily Sunshine ◽

Measured Wind Speed

Average daily data of solar radiation, relative humidity, wind speed and air temperature from 1980 to 2008 are used to estimate the daily reference evapotranspiration in the Mosul City, North of Iraq. ETo calculator software with the Penman Monteith method standardized by the Food and Agriculture Organization is used for calculations. Further, a nonlinear regression approach using SPSS Statistics is utilized to drive the daily reference evapotranspiration relationships in which ETo is function to one or more of the average daily air temperature, actual daily sunshine duration, measured wind speed at 2m height and relative humidity

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AVALIAÇÃO DE DUAS ESTAÇÕES METEOROLÓGICAS AUTOMATIZADAS, PARA ESTIMATIVA DIÁRIA DA EVAPOTRANSPIRAÇÃO DE REFERÊNCIA OBTIDA PELO MÉTODO DE PENMAN-MONTEITH

Irriga ◽

10.15809/irriga.2008v13n3p339-354 ◽

2008 ◽

Vol 13 (3) ◽

pp. 339-354 ◽

Cited By ~ 1

Author(s):

José Eduardo Pitelli Turco ◽

José Carlos Barbosa

Keyword(s):

Regression Analysis ◽

Linear Regression ◽

Meteorological Data ◽

Linear Regression Analysis ◽

Reference Method ◽

Global Solar Radiation ◽

Engineering Department ◽

Weather Stations ◽

Set Up ◽

Reference Crop

AVALIAÇÃO DE DUAS ESTAÇÕES METEOROLÓGICAS AUTOMATIZADAS, PARA ESTIMATIVA DIÁRIA DA EVAPOTRANSPIRAÇÃO DE REFERÊNCIA OBTIDA PELO MÉTODO DE PENMAN-MONTEITH José Eduardo Pitelli Turco1; José Carlos Barbosa21Departamento de Engenharia Rural, Faculdade de Ciências Agrária e Veterinária, Universidade Estadual Paulista, Câmpus de Jaboticabal, Jaboticabal, SP, [email protected] de Ciências Exatas, Faculdade de Ciências Agrária e Veterinária, Universidade Estadual Paulista, Câmpus de Jaboticabal, Jaboticabal, SP 1 RESUMO A finalidade deste trabalho foi a avaliação de estações meteorológicas automatizadas da marca Davis Instruments e Campbell Scientific, procurando detectar possíveis diferenças nas suas medições e estimativas. Foi, também, avaliada, nas duas estações, a integridade dos dados meteorológicos para estimativa da ETo. Os dados meteorológicos avaliados foram os seguintes: radiação solar global, saldo de radiação, temperatura do ar, umidade do ar, velocidade do vento e precipitação pluviométrica. O método de estimativa diária da evapotranspiração de referência avaliado foi o de Penman-Monteith, recomendado pela FAO como método padrão para estimar a ETo. As estações meteorológicas automatizadas da marca Davis Instruments e Campbell Scientific foram instaladas em uma área experimental do Departamento de Engenharia Rural da FCAV/UNESP, Campus de Jaboticabal, SP. Os dados foram coletados diariamente e analisados estatisticamente, por meio de análise de regressão. Foi aplicada uma técnica que verifica a integridade dos dados meteorológicos para estimativa da evapotranspiração de referência. O resultado da avaliação das duas estações, utilizando-se análise de regressão linear, mostra que as estimativas diárias da evapotranspiração de referência (ETo) apresentam diferenças aceitáveis. Aplicando a técnica que verifica a integridade dos dados meteorológicos, verificou-se que os dados de umidade relativa das duas estações e de precipitação da Campbell não foram de boa qualidade. UNITERMOS: evapotranspiração, estações automatizadas, intercomparação. TURCO, J. E. P.; BARBOSA, J. C. TWO AUTOMATIC WEATHER STATIONS METEOROLOGICAL DATA EVALUATION BY PENMAN-MONTEITH REFERENCE EVAPOTRANSPIRATION METHOD 2 ABSTRACT The objective of this study was to evaluate and compare measurements and estimates from Davis and Campbell Scientific Instruments in two automatic weather stations. Integrity of meteorological data for estimates of evapotranspiration of reference crop (ETo) from both stations was also evaluated. The following meteorological data were evaluated: air temperature, air humidity, wind speed, precipitation, net radiation and global solar radiation. The Penman-Monteith reference method to estimate ETo was evaluated daily. The weather stations were set up in an experimental area of the Rural Engineering Department- FACV/UNESP, in Jaboticabal, State of Sao Paulo. Data were collected daily and statistical analysis was performed using linear regression analysis. The integrity of meteorological data to estimate ETo was evaluated. The results of the study in the stations using linear regression analysis showed that daily estimates for ETo had acceptable differences. The technique which evaluates the integrity of meteorological data revealed that data of relative humidity from both stations and of precipitation using Campbell Instruments were not good. KEY WORDS: evapotranspiration, automatic weather station, intercomparison

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Attributing the Changes in Reference Evapotranspiration in Southwestern China Using a New Separation Method

Journal of Hydrometeorology ◽

10.1175/jhm-d-16-0118.1 ◽

2017 ◽

Vol 18 (3) ◽

pp. 777-798 ◽

Cited By ~ 19

Author(s):

Shanlei Sun ◽

Haishan Chen ◽

Ge Sun ◽

Weimin Ju ◽

Guojie Wang ◽

...

Keyword(s):

Reference Evapotranspiration ◽

Separation Method ◽

Southwestern China ◽

Complete Analysis ◽

Physical Mechanisms ◽

Food And Agriculture ◽

Food And Agriculture Organization ◽

Monthly Changes ◽

Meteorological Observations ◽

New Perspective

Abstract This study investigated monthly and annual reference evapotranspiration changes over southwestern China (SWC) from 1960 to 2012, using the Food and Agriculture Organization of the United Nations’ report 56 (FAO-56) Penman–Monteith equation and routine meteorological observations at 269 weather sites. During 1960–2012, the monthly and annual decreased at most sites. Moreover, the SWC regional average trend in annual was significantly negative (p < 0.05); this trend was the same in most months. A new separation method using several numerical experiments was proposed to quantify each driving factor’s contribution to changes and exhibited higher accuracy based on several validation criteria, after which an attribution analysis was performed. Across SWC, the declining annual was mainly due to decreased net radiation (RN). Spatially, the annual changes at most sites in eastern SWC (excluding southeastern West Guangxi) were generally due to RN, whereas wind speed (WND) or vapor pressure deficit (VPD) was the determinant at other sites. Nevertheless, the determinants differed among 12 months. For the whole SWC, increased VPD in February and decreased WND in April, May, and October were the determinant of decreased ; however, decreased RN was the determinant in other months. Overall, the determinant of the monthly changes exhibited a complex spatial pattern. A complete analysis of changes and the related physical mechanisms in SWC is necessary to better understand hydroclimatological extremes (e.g., droughts) and to develop appropriate strategies to sustain regional development (e.g., water resources and agriculture). Importantly, this separation method provides new perspective for quantitative attribution analyses and thus may be implemented in various scientific fields (e.g., climatology and hydrology).

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Analysis of seven indirect methods for evaluation of reference evapotranspiration under climate conditions of Serbia

Journal of Agricultural Sciences Belgrade ◽

10.2298/jas1801067i ◽

2018 ◽

Vol 63 (1) ◽

pp. 67-81

Author(s):

Dzenita Idrizovic ◽

Gordana Matovic ◽

Enika Gregoric ◽

Ruzica Stricevic

Keyword(s):

Reference Evapotranspiration ◽

Vegetation Period ◽

Weather Data ◽

Special Importance ◽

Climate Conditions ◽

Food And Agriculture ◽

Food And Agriculture Organization ◽

Using Data ◽

Novi Sad ◽

Taylor Methods

In order to calculate water deficit of agricultural crops, it is necessary to have an insight into the evapotranspiration process. As for evaluation of reference evapotranspiration, the Penman-Monteith (FAO56-PM) method, suggested by The International Commission on Irrigation and Drainage (ICID) and Food and Agriculture Organization of the United Nations (FAO), requires several climate parameters, which are often unavailable. Thus, in this paper, the methods for computing ETo, which use limited weather data, were tested and then compared to FAO56-PM. The selected methods were those most often used as the replacement for FAO56-PM: Hargreaves, adjusted Hargreaves, Copais, Turc, Priestley-Taylor, Makkink and Hamon. ETo was calculated at the daily and average monthly levels, for the 2010-2013 period, using data from the following meteorological stations: Nis, Belgrade, Novi Sad, Loznica, Valjevo, Zlatibor, Cuprija and Kikinda. Special importance was given to the vegetation period during the dry season due to the application of irrigation. The comparison of methods was based on statistical analysis, using parameters: MXE, MAE, RMSD, ARMSD, WRMSD, b and R2. The highest rate of matching FAO-PM at the average monthly level, as well as during the 2012 growing season, was shown by Copais, Turc and Priestley-Taylor methods, thus these methods may be recommended as the replacement for FAOPM under climate conditions of Serbia. In case only temperature data are available, the results of this research justify the use of the adjusted Hargreaves equation to calculate ETo for the vegetation period.

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Evaluation of the FAO Penman–Montheith, Priestley–Taylor and Hargreaves models for estimating reference evapotranspiration in southern Malawi

Hydrology Research ◽

10.2166/nh.2012.224 ◽

2012 ◽

Vol 44 (4) ◽

pp. 706-722 ◽

Cited By ~ 23

Author(s):

Cosmo Ngongondo ◽

Chong-Yu Xu ◽

Lena M. Tallaksen ◽

Berhanu Alemaw

Keyword(s):

Wind Speed ◽

Relative Humidity ◽

Vapour Pressure ◽

Reference Evapotranspiration ◽

Climate Variables ◽

Limited Data ◽

Full Data ◽

Data Intensive ◽

Food And Agriculture ◽

Food And Agriculture Organization

This study evaluated the performance of the Food and Agriculture Organization (FAO) Penman–Monteith (PM) reference evapotranspiration (ET0) method for various limited data scenarios in southern Malawi. The study further evaluated the full data PM method against the radiation-based Priestley–Taylor (PT) and the temperature-based Hargreaves (HAG) methods, which are less data-intensive approaches commonly used to estimate ET0 in data-scarce situations. A comprehensive daily climate dataset observed at the Nchalo Sugar Estate in southern Malawi for the period 1971–2007 was the basis of the study. The results suggested that lack of data on wind speed and actual vapour pressure did not significantly affect the PM ET0 estimates. However, the estimation of radiation using various combinations of observed wind speed and relative humidity all resulted in significant deviations from the PM ET0. Further, the HAG and PT methods significantly underestimated the PM. However, the PM method computed with estimated climate variables instead of observed climate variables still outperformed both the PT and HAG methods if their original parameters and estimated radiation were used. Thus, new monthly parameters for the PT and the HAG methods are proposed for more accurate daily ET0 estimates.

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