Hybrid Genetic Algorithm−Based BP Neural Network Models Optimize Estimation Performance of Reference Crop Evapotranspiration in China

Precise estimation of reference evapotranspiration (ET<sub>0</sub>) is of significant importance in hydrologic processes. In this study, a genetic algorithm (GA) optimized back propagation (BP) neural network model was developed to estimate ET<sub>0</sub> using different comb...

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Main Authors: Anzhen Qin, Zhilong Fan, Liuzeng Zhang
Format: Article
Language:English
Published: MDPI AG 2022-10-01
Series:Applied Sciences
Subjects:
Online Access:https://www.mdpi.com/2076-3417/12/20/10689
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author Anzhen Qin
Zhilong Fan
Liuzeng Zhang
author_facet Anzhen Qin
Zhilong Fan
Liuzeng Zhang
author_sort Anzhen Qin
collection DOAJ
description Precise estimation of reference evapotranspiration (ET<sub>0</sub>) is of significant importance in hydrologic processes. In this study, a genetic algorithm (GA) optimized back propagation (BP) neural network model was developed to estimate ET<sub>0</sub> using different combinations of meteorological data across various climatic zones and seasons in China. Fourteen climatic locations were selected to represent five major climates. Meteorological datasets in 2018–2020, including maximum, minimum and mean air temperature (T<sub>max</sub>, T<sub>min</sub>, T<sub>mean</sub>, °C) and diurnal temperature range (∆T, °C), solar radiation (R<sub>a</sub>, MJ m<sup>−2</sup> d<sup>−1</sup>), sunshine duration (S, h), relative humidity (RH, %) and wind speed (U<sub>2</sub>, m s<sup>−1</sup>), were first subjected to correlation analysis to determine which variables were suitable as input parameters. Datasets in 2018 and 2019 were utilized for training the models, while datasets in 2020 were for testing. Coefficients of determination (r<sup>2</sup>) of 0.50 and 0.70 were adopted as threshold values for selection of correlated variables to run the models. Results showed that U<sub>2</sub> had the least r<sup>2</sup> with ET<sub>0</sub>, followed by ∆T. T<sub>max</sub> had the greatest r<sup>2</sup> with ET<sub>0</sub>, followed by T<sub>mean</sub>, R<sub>a</sub> and T<sub>min</sub>. GA significantly improved the performance of BP models across different climatic zones, with the accuracy of GABP models significantly higher than that of BP models. GABP<sub>0.5</sub> model (input variables based on r<sup>2</sup> > 0.50) had the best ET<sub>0</sub> estimation performance for different seasons and significantly reduced estimation errors, especially for autumn and winter seasons whose errors were larger with other BP and GABP models. GABP<sub>0.5</sub> model using radiation/temperature data is highly recommended as a promising tool for modelling and predicting ET<sub>0</sub> in various climatic locations.
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spelling doaj.art-2280616254774d99b544cc2b915d8f102023-11-23T22:48:50ZengMDPI AGApplied Sciences2076-34172022-10-0112201068910.3390/app122010689Hybrid Genetic Algorithm−Based BP Neural Network Models Optimize Estimation Performance of Reference Crop Evapotranspiration in ChinaAnzhen Qin0Zhilong Fan1Liuzeng Zhang2State Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, ChinaState Key Laboratory of Aridland Crop Science, Gansu Agricultural University, Lanzhou 730070, ChinaCollege of Software, Henan Normal University, Xinxiang 453007, ChinaPrecise estimation of reference evapotranspiration (ET<sub>0</sub>) is of significant importance in hydrologic processes. In this study, a genetic algorithm (GA) optimized back propagation (BP) neural network model was developed to estimate ET<sub>0</sub> using different combinations of meteorological data across various climatic zones and seasons in China. Fourteen climatic locations were selected to represent five major climates. Meteorological datasets in 2018–2020, including maximum, minimum and mean air temperature (T<sub>max</sub>, T<sub>min</sub>, T<sub>mean</sub>, °C) and diurnal temperature range (∆T, °C), solar radiation (R<sub>a</sub>, MJ m<sup>−2</sup> d<sup>−1</sup>), sunshine duration (S, h), relative humidity (RH, %) and wind speed (U<sub>2</sub>, m s<sup>−1</sup>), were first subjected to correlation analysis to determine which variables were suitable as input parameters. Datasets in 2018 and 2019 were utilized for training the models, while datasets in 2020 were for testing. Coefficients of determination (r<sup>2</sup>) of 0.50 and 0.70 were adopted as threshold values for selection of correlated variables to run the models. Results showed that U<sub>2</sub> had the least r<sup>2</sup> with ET<sub>0</sub>, followed by ∆T. T<sub>max</sub> had the greatest r<sup>2</sup> with ET<sub>0</sub>, followed by T<sub>mean</sub>, R<sub>a</sub> and T<sub>min</sub>. GA significantly improved the performance of BP models across different climatic zones, with the accuracy of GABP models significantly higher than that of BP models. GABP<sub>0.5</sub> model (input variables based on r<sup>2</sup> > 0.50) had the best ET<sub>0</sub> estimation performance for different seasons and significantly reduced estimation errors, especially for autumn and winter seasons whose errors were larger with other BP and GABP models. GABP<sub>0.5</sub> model using radiation/temperature data is highly recommended as a promising tool for modelling and predicting ET<sub>0</sub> in various climatic locations.https://www.mdpi.com/2076-3417/12/20/10689BP modelsclimatic zonesmodel performancemulti−layer perceptronseasons
spellingShingle Anzhen Qin
Zhilong Fan
Liuzeng Zhang
Hybrid Genetic Algorithm−Based BP Neural Network Models Optimize Estimation Performance of Reference Crop Evapotranspiration in China
Applied Sciences
BP models
climatic zones
model performance
multi−layer perceptron
seasons
title Hybrid Genetic Algorithm−Based BP Neural Network Models Optimize Estimation Performance of Reference Crop Evapotranspiration in China
title_full Hybrid Genetic Algorithm−Based BP Neural Network Models Optimize Estimation Performance of Reference Crop Evapotranspiration in China
title_fullStr Hybrid Genetic Algorithm−Based BP Neural Network Models Optimize Estimation Performance of Reference Crop Evapotranspiration in China
title_full_unstemmed Hybrid Genetic Algorithm−Based BP Neural Network Models Optimize Estimation Performance of Reference Crop Evapotranspiration in China
title_short Hybrid Genetic Algorithm−Based BP Neural Network Models Optimize Estimation Performance of Reference Crop Evapotranspiration in China
title_sort hybrid genetic algorithm based bp neural network models optimize estimation performance of reference crop evapotranspiration in china
topic BP models
climatic zones
model performance
multi−layer perceptron
seasons
url https://www.mdpi.com/2076-3417/12/20/10689
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AT zhilongfan hybridgeneticalgorithmbasedbpneuralnetworkmodelsoptimizeestimationperformanceofreferencecropevapotranspirationinchina
AT liuzengzhang hybridgeneticalgorithmbasedbpneuralnetworkmodelsoptimizeestimationperformanceofreferencecropevapotranspirationinchina