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Assessment of pan coefficient models for the estimation of the reference evapotranspiration in a Mediterranean environment in Turkey

Reference evapotranspiration (ETo) is essential for irrigation practices and the management of water resources and plays a vital role in agricultural and hydro-meteorological studies. The FAO-56 Penman-Monteith (PM) equation, recommended as the sole standard method of calculating ETo by the Food and...

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Autor principal: Koç, Deniz Levent
Formato: Online Artículo Texto
Lenguaje:English
Publicado: PeerJ Inc. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9188310/
https://www.ncbi.nlm.nih.gov/pubmed/35698619
http://dx.doi.org/10.7717/peerj.13554
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author Koç, Deniz Levent
author_facet Koç, Deniz Levent
author_sort Koç, Deniz Levent
collection PubMed
description Reference evapotranspiration (ETo) is essential for irrigation practices and the management of water resources and plays a vital role in agricultural and hydro-meteorological studies. The FAO-56 Penman-Monteith (PM) equation, recommended as the sole standard method of calculating ETo by the Food and Agriculture Organization of the United Nations (FAO), is the most commonly used and accurate model to determine the ETo and evaluate ETo equations. However, it requires many meteorological variables, often restricting its applicability in regions with poor or missing meteorological observations. Many empirical and semi-empirical equations have been developed to predict the ET(0) from numerous meteorological data. The FAO-24 Pan method is commonly used worldwide to estimate ETo because it is simple and requires only pan coefficients. However, pan coefficients (K(pan)) should be determined accurately to estimate ET(0) using the FAO-24 Pan method. As the accuracy and reliability of the K(pan) models can be different from one location to another, they should be tested or calibrated for different climates and surrounding conditions. In this study, the performance of the eight K(pan) models was evaluated using 22-year daily climate data for the summer growing season in Adana, which has a Mediterranean climate in Turkey. The results showed that the mean seasonal pan coefficients estimated by all K(pan) models differed significantly at a 1% significance level from those observed by FAO-56 PM according to the two-tail z test. In the study, ETo values estimated by K(pan) models were compared against those obtained by the FAO-56 PM equation. The seasonal and monthly performance of K(pan) models was varied, and the Wahed & Snyder model presented the best performance for ETo estimates at the seasonal scale. (RMSE = 0.550 mm d(−1); MAE = 0.425 mm d(−1); MBE = −0.378 mm d(−1); RE = 0.134). In addition, it showed a good performance in estimating ETo on a monthly scale. The Orang model showed the lowest performance in estimating ETo among all models, with a very high relative error on the seasonal scale. (RMSE = 1.867 mm d(−1); MAE = 1.806 mm d(−1); MBE = −1.806 mm d(−1); RE = 0.455). In addition, it showed the poorest performance on a monthly scale. Hence, the Wahed & Snyder model can be considered to estimate ETo under Adana region conditions after doing the necessary calibration.
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spelling pubmed-91883102022-06-12 Assessment of pan coefficient models for the estimation of the reference evapotranspiration in a Mediterranean environment in Turkey Koç, Deniz Levent PeerJ Agricultural Science Reference evapotranspiration (ETo) is essential for irrigation practices and the management of water resources and plays a vital role in agricultural and hydro-meteorological studies. The FAO-56 Penman-Monteith (PM) equation, recommended as the sole standard method of calculating ETo by the Food and Agriculture Organization of the United Nations (FAO), is the most commonly used and accurate model to determine the ETo and evaluate ETo equations. However, it requires many meteorological variables, often restricting its applicability in regions with poor or missing meteorological observations. Many empirical and semi-empirical equations have been developed to predict the ET(0) from numerous meteorological data. The FAO-24 Pan method is commonly used worldwide to estimate ETo because it is simple and requires only pan coefficients. However, pan coefficients (K(pan)) should be determined accurately to estimate ET(0) using the FAO-24 Pan method. As the accuracy and reliability of the K(pan) models can be different from one location to another, they should be tested or calibrated for different climates and surrounding conditions. In this study, the performance of the eight K(pan) models was evaluated using 22-year daily climate data for the summer growing season in Adana, which has a Mediterranean climate in Turkey. The results showed that the mean seasonal pan coefficients estimated by all K(pan) models differed significantly at a 1% significance level from those observed by FAO-56 PM according to the two-tail z test. In the study, ETo values estimated by K(pan) models were compared against those obtained by the FAO-56 PM equation. The seasonal and monthly performance of K(pan) models was varied, and the Wahed & Snyder model presented the best performance for ETo estimates at the seasonal scale. (RMSE = 0.550 mm d(−1); MAE = 0.425 mm d(−1); MBE = −0.378 mm d(−1); RE = 0.134). In addition, it showed a good performance in estimating ETo on a monthly scale. The Orang model showed the lowest performance in estimating ETo among all models, with a very high relative error on the seasonal scale. (RMSE = 1.867 mm d(−1); MAE = 1.806 mm d(−1); MBE = −1.806 mm d(−1); RE = 0.455). In addition, it showed the poorest performance on a monthly scale. Hence, the Wahed & Snyder model can be considered to estimate ETo under Adana region conditions after doing the necessary calibration. PeerJ Inc. 2022-06-08 /pmc/articles/PMC9188310/ /pubmed/35698619 http://dx.doi.org/10.7717/peerj.13554 Text en ©2022 Koç https://creativecommons.org/licenses/by/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0/) , which permits unrestricted use, distribution, reproduction and adaptation in any medium and for any purpose provided that it is properly attributed. For attribution, the original author(s), title, publication source (PeerJ) and either DOI or URL of the article must be cited.
spellingShingle Agricultural Science
Koç, Deniz Levent
Assessment of pan coefficient models for the estimation of the reference evapotranspiration in a Mediterranean environment in Turkey
title Assessment of pan coefficient models for the estimation of the reference evapotranspiration in a Mediterranean environment in Turkey
title_full Assessment of pan coefficient models for the estimation of the reference evapotranspiration in a Mediterranean environment in Turkey
title_fullStr Assessment of pan coefficient models for the estimation of the reference evapotranspiration in a Mediterranean environment in Turkey
title_full_unstemmed Assessment of pan coefficient models for the estimation of the reference evapotranspiration in a Mediterranean environment in Turkey
title_short Assessment of pan coefficient models for the estimation of the reference evapotranspiration in a Mediterranean environment in Turkey
title_sort assessment of pan coefficient models for the estimation of the reference evapotranspiration in a mediterranean environment in turkey
topic Agricultural Science
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9188310/
https://www.ncbi.nlm.nih.gov/pubmed/35698619
http://dx.doi.org/10.7717/peerj.13554
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