scholarly journals Analysis of the NASA-POWER system for estimating reference evapotranspiration in the Comarca Lagunera, Mexico

2021 ◽  
Vol 13 (2) ◽  
pp. 201-226
Author(s):  
Sergio Iván Jiménez-Jiménez ◽  
◽  
Waldo Ojeda-Bustamante ◽  
Marco Antonio Inzunza-Ibarra ◽  
Mariana de Jesús Marcial-Pablo ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Solar Radiation ◽  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Reanalysis Data ◽  
Measured Data ◽  
System Data ◽  
Data Source

Introduction: The FAO-56 Penman-Monteith (PM) is one of the most solid and commonly used methods for estimating reference evapotranspiration (ETo); however, it requires meteorological data that are not always available, so an alternative is the use of reanalysis data. Objective: To estimate the error that the NASA-POWER (NP) system data can generate in the ETo of the Comarca Lagunera, Mexico. Methodology: Daily and decadal average ETo were estimated in five different ways. In each case, a different method was used to estimate ETo (FAO-56 PM or Hargreaves and Samani [HS]) and a different meteorological data source (measured, NP data or combination of both). Results: NP data can be used to provide temperature, solar radiation and relative humidity variables, but not wind speed. The NP data overestimate the measured ETo, an RMSE of 1.15 and 0.89 mm∙d-1 was found for daily and decadal periods, respectively. Limitations of the study: A grid error analysis could not be carried out because the number of stations is limited. Originality: The use of reanalysis data to estimate ETo has not been analyzed locally. Conclusion: When measured data are not available, NP data and the HS equation can be used. When using the FAO-56 PM method and NP data, the in situ wind speed must be available.

scholarly journals Comparative Study of Evapotranspiration Variation and its Relationship with other Climatic Parameters in Asaba and Uyo

2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Okwunna M Umego ◽  
Temitayo A Ewemoje ◽  
Oluwaseun A Ilesanmi
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Solar Radiation ◽  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Small Variation ◽  
Climatic Variables ◽  
Maximum Temperature ◽  
Climatic Parameters ◽  
Sunshine Hours

This study was carried out to assess the variations of Reference Evapotranspiration (ETO also denoted with RET) calculated using FAO-56 Penman Monteith model of two locations Asaba and Uyo and evaluate its relationships with the variations of other climatic parameters. Meteorological data of forty one years (1975-2015) and thirty five years (1981-2015) period for Asaba and Uyo, respectively gotten from Nigeria Meteorological Agency, Abuja were used. It was observed that the variations of Evapotranspiration (ET) in both locations were in line with two seasons (rainy and dry) normally experienced in Nigeria having its highest value in March (4.8 mm/day) for Asaba and for Uyo in February (4.5 mm/day); and its lowest value in August (3.1 mm/day) for Asaba and in July (2.9 mm/day) for Uyo. ET variation when compared with other climatic variables in both locations was observed to have the same trend with maximum temperature, solar radiation and sunshine hours. It also has the same variation with minimum temperature though with slight deviation. It was observed that ET variation is inversely proportional to the variation relative humidity. Wind speed displayed relatively small variation in its trend over the study period and is not in line with the variations of ET.Keywords— Evapotranspiration, Climatic Variables, FAO Penman-Monteith Model, Variations

scholarly journals Performance of different methods for reference evapotranspiration estimation in Jaíba, Brazil

2018 ◽  
Vol 22 (2) ◽  
pp. 83-89 ◽  
Author(s):  
Gustavo H. da Silva ◽  
Santos H. B. Dias ◽  
Lucas B. Ferreira ◽  
Jannaylton É. O. Santos ◽  
Fernando F. da Cunha
Keyword(s):  
Wind Speed ◽  
Solar Radiation ◽  
Standard Method ◽  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Air Humidity ◽  
Method Performance ◽  
Relative Air Humidity ◽  
Evapotranspiration Estimation ◽  
Missing Variables

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.

Sensitivity analysis of different evapotranspiration methods using a new sensitivity coefficient

2013 ◽  
Vol 14 (3) ◽  
pp. 335-343 ◽  
Keyword(s):  
Sensitivity Analysis ◽  
Wind Speed ◽  
Relative Humidity ◽  
Solar Radiation ◽  
Partial Derivative ◽  
Reference Evapotranspiration ◽  
Sensitivity Coefficient ◽  
Meteorological Variables ◽  
Sensitivity Coefficients ◽  
Irrigation Period

The estimation of evapotranspiration is essential in water resources management. Among a group of methods, the Penman–Monteith has been commonly applied to calculate reference evapotranspiration as this method has been also recommended by the Food and Agriculture Organization of the U.N. (FAO). Other methods widely used are: the FAO 24 Penman, the modified Blaney and Criddle, the FAO 24 Makkink, and the Hargreaves. Sensitivity analysis is required to gain a better understanding of the meteorological systems; particularly to indicate the physical meaning of each meteorological parameter used in the estimation of the reference evapotranspiration. Several dimensionless sensitivity coefficients have been proposed, based on the partial derivative of the dependent variable (reference evapotranspiration) to the independent variables (meteorological variables). In this paper, a new sensitivity coefficient is proposed to drive sensitivity analysis of the evapotranspiration methods. The new sensitivity coefficient uses the partial derivative and the standard deviation of each independent variable. The meteorological variables, whose influence has been examined, are all the necessary meteorological parameters for the calculation of reference evapotranspiration, such as temperature, solar radiation, wind speed and relative humidity for each method. Data from the automatic meteorological station of Aminteo in the Prefecture of Florina, Western Macedonia, were used. The sensitivity coefficients were calculated for each month, year and irrigation period. The comparison of the sensitivity coefficients is performed for the month of water peak demand (July), the irrigation period and the year for each evapotranspiration method. Results show that the influence of the variables to evapotranspiration is not the same for each period, and also the order that the variables influence evapotranspiration is changing. A comparison between the five evapotranspiration methods shows that solar radiation and temperature are the main parameters that affect evapotranspiration, while relative humidity and wind speed are not so important for the calculation of evapotranspiration.

scholarly journals Evaluation of FAO-56 Procedures for Estimating Reference Evapotranspiration Using Missing Climatic Data for a Brazilian Tropical Savanna

Water ◽  
2021 ◽  
Vol 13 (13) ◽  
pp. 1763
Author(s):  
Luiz Claudio Galvão do Valle Júnior ◽  
George L. Vourlitis ◽  
Leone Francisco Amorim Curado ◽  
Rafael da Silva Palácios ◽  
José de S. Nogueira ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Water Resource Management ◽  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Climatic Conditions ◽  
Climatic Variables ◽  
Climatic Data ◽  
Wet Season ◽  
Radiation Data

The Brazilian savanna (Cerrado) has been heavily impacted by agricultural activities over the last four to five decades, and reliable estimates of reference evapotranspiration (ETo) are needed for water resource management and irrigation agriculture. The Penman–Monteith (PM) is one of the most accepted models for ETo estimation, but it requires many inputs that are not commonly available. Therefore, assessing the FAO guidelines to compute ETo when meteorological data are missing could lead to a better understanding of which variables are critically important for reliable estimates of ETo and how climatic variables are related to water requirements and atmospheric demands. In this study, ETo was computed for a grass-dominated part of the Cerrado from April 2010 to August 2019. We tested 12 different scenarios considering radiation, relative humidity, and/or wind speed as missing climatic data using guidelines given by the FAO. Our results presented that wind speed and actual vapor pressure do not affect ETo estimates as much as the other climatic variables; therefore, in the Cerrado’s conditions, wind speed and relative humidity measurements are less required than temperature and radiation data. When radiation data were missing, the computed ETo was overestimated compared to the benchmark. FAO procedures to estimate the net radiation presented good results during the wet season; however, during the dry season, their results were overestimated because the method could not estimate negative Rn. Our results indicate that radiation data have the highest impact on ETo for our study area and presumably for regions with similar climatic conditions. In addition, those FAO procedures for estimating radiation are not suitable when radiation data are missing.

scholarly journals Evaluation of FAO-56 procedures for estimating reference evapotranspiration using missing climatic data for a Brazilian tropical savanna

2021 ◽  
Author(s):  
Luiz Claudio Valle Junior ◽  
George Vourlitis ◽  
Leone Francisco Curado ◽  
Rafael Palacios ◽  
José Nogueira ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Climatic Data ◽  
Wet Season ◽  
Resources Management ◽  
Radiation Data ◽  
D Values ◽  
Irrigation Agriculture

Since the Brazilian Cerrado has been heavily impacted by agricultural activities over the last four to five decades, reference evapotranspiration (ETo) plays a pivotal role in water resources management for irrigation agriculture. The Penman-Monteith (PM) is one of the most accepted models for ETo estimation, but it requires many inputs that are not commonly available. Therefore, assessing the FAO guidelines to compute ETo when meteorological data are missing could lead to a better understanding of how climatic variables are related to water requirements and atmospheric demands for a grass-mixed savanna region and which variable impacts the estimates the most. In this study, ETo was computed from April 2010 to August 2019. We tested twelve different scenarios considering radiation, relative humidity, and/or wind speed as missing climatic data using guidelines given by FAO. When wind speed and/or relative humidity data were the only missing data, the PM method showed the lowest errors in the ETo estimates and correlation coefficient (r) and Willmott’s index of agreement (d) values close to 1.0. When radiation data were missing, computed ETo was overestimated compared to the benchmark. FAO procedures to estimate the net radiation presented good results during the wet season; however, during the dry season, their results were overestimated, especially because the method could not estimate negative Rn. Therefore, we can infer that radiation data have the highest impact on ETo for our study area and also regions with similar conditions and FAO guidelines are not suitable when radiation data are missing.

scholarly journals ESTUDO COMPARATIVO DA EVAPOTRANSPIRAÇÃO DE REFERÊNCIA ENTRE LOCALIDADES NO ESTADO DE SÃO PAULO E NA PROVÍNCIA DE HABANA

Irriga ◽  
2018 ◽  
Vol 21 (2) ◽  
pp. 395 ◽  
Author(s):  
Francisca Franciana Sousa Pereira ◽  
Enzo Dal Pai ◽  
Ranses J. Vázquez Montenegro ◽  
Rodrigo Máximo Sánchez Román ◽  
Alba Maria Guadalupe Orellana González ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Solar Radiation ◽  
Reference Evapotranspiration ◽  
Sao Paulo ◽  
São Paulo ◽  
Paulo State ◽  
The Difference ◽  
The One ◽  
E Mail

ESTUDO COMPARATIVO DA EVAPOTRANSPIRAÇÃO DE REFERÊNCIA ENTRE LOCALIDADES NO ESTADO DE SÃO PAULO E NA PROVÍNCIA DE HABANA FRANCISCA FRANCIANA SOUSA PEREIRA1; ENZO DAL PAI2; RANSES J. VÁZQUEZ MONTENEGRO3; RODRIGO MÁXIMO SÁNCHEZ ROMÁN4; ALBA MARÍA GUADALUPE ORELLANA GONZÁLEZ5 E JOÃO FRANCISCO ESCOBEDO6 1Professora Depto. de Engenharia Rural - UNESP/FCA, C.P. 237; CEP: 18610-307 –  Botucatu, SP – Brasil. E-mail autor principal: [email protected] Depto. de Engenharia Rural - UNESP/FCA, Botucatu, SP – Brasil.3Geográfo, Especialista em Meteorología agrícola do Centro de Meteorología Agrícola, Instituto de Meteorología La Habana, Cuba.4Professor Depto. de Engenharia Rural - UNESP/FCA, Botucatu, SP – Brasil.5Pós- Doutora Depto. de Engenharia Rural - UNESP/FCA, Botucatu, SP - Brasil.6Professor Depto. de Engenharia Rural - UNESP/FCA, Botucatu, SP – Brasil.  1 RESUMO A FAO propôs a evapotranspiração de referência (ETo) a fim de comparar a evapotranspiração em diferentes regiões, isso porque a maioria das equações empregadas na estimativa da evapotranspiração são empíricas e limitadas a serem usadas para locais e climas similares àqueles em que as mesmas foram determinadas. O objetivo deste estudo foi analisar a diferença nos valores calculados de ETo para Botucatu e Piracicaba (Brasil) e Güira de Melena (Cuba), em uma base de dados de 30 anos, trabalhada na partição diária. Avaliaram-se diferenças sazonais entre os anos e entre as localidades e posteriormente a influência dos climas locais nestas diferenças dos valores de ETo. Os elementos climáticos temperatura máxima e mínima do ar, umidade relativa do ar, velocidade do vento a 2 m de altura e insolação foram obtidos das estações meteorológicas convencionais. Os valores da evapotranspiração em Cuba foram maiores durante os meses de verão no Hemisfério Norte. Os maiores valores de evapotranspiração em Botucatu e Piracicaba ocorreram nos meses de verão no hemisfério Sul. Existe correlação entre as três localidades mesmo com a distância entre as mesmas. Palavras-chave: demanda hídrica, irrigação, recursos hídricos, Penman-Monteith  SOUSA PEREIRA F. F.; DAL PAI, E.; VÁZQUEZ MONTENEGRO, R. J.; SÁNCHEZ ROMÁN, R. M.; ORELLANA GONZÁLEZ, A. M. G.; ESCOBEDO, J. F. COMPARATIVE STUDY OF REFERENCE EVAPOTRANSPIRATION BETWEEN LOCALITIES IN SÃO PAULO STATE AND IN THE HABANA PROVINCE  2 ABSTRACT FAO proposed the reference evapotranspiration to compare evapotranspiration in different areas, because most equations employed in estimating evapotranspiration are empirical and limited to be used for in local and climates similar to those in which they were determined. The objective of this study was to analyze the difference in the calculated values of ETo for Botucatu and Piracicaba (Brazil) and Güira Melena (Cuba), on a basis ofbased on 30- years of  data. Were evaluated sSeasonal differences between years and between locations were assessed and subsequently the influence of local climates on these ETo values differences in the values of ETo. The cClimatic elements maximum (Tmax) and minimum temperature (Tmax) and minimum (Tmin), relative humidity (RH), wind speed at 2 m height (U2) and solar radiation (n) were obtained from conventional meteorological stations. The values of eEvapotranspiration values in Cuba were higher during the summer months in the Northern Hemisphere. The highest values of evapotranspiration values in Botucatu and Piracicaba occurred in the summer months in the Southern Hemisphere. Correlation exists between the three locations with the same distance between them. It was concluded from the methodology used that the three localities have different values of evapotranspiration values and despite being in different hemispheres the evapotranspiration among Piracicaba and Güira Melena are closer than the one verified between Botucatu and Piracicaba. Keywords: water requirement, evapotranspiration, irrigation, water resources, Penman Monteith

scholarly journals Evaluation of FAO-56 Procedures for Estimating Reference Evapotranspiration Using Missing Climatic Data for a Brazilian Tropical Savanna

2021 ◽  
Author(s):  
Luiz Cláudio Galvão Valle Júnior ◽  
George Louis Vourlitis ◽  
Leone Francisco Amorim Curado ◽  
Rafael da Silva Palácios ◽  
José de Souza Nogueira ◽  
...  
Keyword(s):  
Wind Speed ◽  
Relative Humidity ◽  
Reference Evapotranspiration ◽  
Meteorological Data ◽  
Climatic Data ◽  
Wet Season ◽  
Resources Management ◽  
Radiation Data ◽  
D Values ◽  
Irrigation Agriculture

Abstract Since the Brazilian Cerrado has been heavily impacted by agricultural activities over the last four to five decades, reference evapotranspiration (ETo) plays a big role in water resources management for irrigation agriculture. The Penman-Monteith (PM) is one of the most accepted models for ETo estimation, but it requires many inputs that are not commonly available. Therefore, assessing the FAO guidelines to compute ETo when meteorological data are missing could lead to a better understanding of how climatic variables are related to water requirements and atmospheric demands for a grass-mixed savanna region and which variable impacts the estimates the most. ETo was computed from April 2010 to August 2019. We tested twelve different scenarios considering radiation, relative humidity, and/or wind speed as missing climatic data using guidelines given by FAO. When wind speed and/or relative humidity data were the only missing data, the PM method showed the lowest errors in the ETo estimates and correlation coefficient (r) and Willmott’s index of agreement (d) values close to 1.0. When radiation data were missing, computed ETo was overestimated compared to the benchmark. FAO procedures to estimate net radiation presented good results during the wet season; however, during the dry season, their results were overestimated, especially because the method could not estimate negative Rn. Therefore, we can infer that radiation data have the largest impact on ETo for our study area and regions with similar conditions and FAO guidelines are not suitable when radiation data are missing.

Statistical Analysis of Weather Effects on PM2.5

2012 ◽  
Vol 610-613 ◽  
pp. 1033-1040
Author(s):  
Wei Dai ◽  
Jia Qi Gao ◽  
Bo Wang ◽  
Feng Ouyang
Keyword(s):  
Statistical Analysis ◽  
Wind Speed ◽  
Relative Humidity ◽  
Statistical Methods ◽  
Predictive Analytics ◽  
Hypothesis Test ◽  
Meteorological Data ◽  
Weather Conditions ◽  
Statistical Distribution ◽  
Weather Effects

Effects of weather conditions including temperature, relative humidity, wind speed, wind and direction on PM2.5 were studied using statistical methods. PM2.5 samples were collected during the summer and the winter in a suburb of Shenzhen. Then, correlations, hypothesis test and statistical distribution of PM2.5 and meteorological data were analyzed with IBM SPSS predictive analytics software. Seasonal and daily variations of PM2.5 have been found and these mainly resulted from the weather effects.

Empirical Equations to Estimate Evapotranspiration in Mosul City

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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