Sensitivity analysis of the reference crop evapotranspiration in a humid region

Biazar, Seyed Mostafa; Dinpashoh, Yagob; Singh, Vijay P.

doi:10.1007/s11356-019-06419-w

Cited by 37 publications

(20 citation statements)

References 42 publications

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“…But the dominant factor is different in different regions and at different scales. At present, research of evapotranspiration and meteorological elements is concentrated in large areas, such as countries 8 , provinces 14 , and watersheds 29 while research on evapotranspiration in small watersheds is relatively rare and the research methods and systems used are not standardized. In addition, there are few literature studies on the seasonal and monthly variation trend analysis of ET p in temperate monsoon regions with significant dry and wet climates and the main meteorological factors affecting ET p .…”

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confidence: 99%

Analysis of the variation in potential evapotranspiration and surface wet conditions in the Hancang River Basin, China

Zhang

Wang

2021

Sci Rep

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Evapotranspiration is an important component of the water cycle, and possible trends in evapotranspiration can, among others, influence water management and agricultural production. Potential evapotranspiration (ETp) is a measure of the ability of the atmosphere to remove water from the surface through the processes of evaporation and transpiration. It plays an important role in assessing regional dry–wet conditions and variations in meteorological conditions. This study analyzed the change trends of monthly ETp and surface dryness and wetness in the Hancang River Basin and, through principal component analysis and correlation analysis, explored the main meteorological factors that affected ETp and the interactions between meteorological factors; ETp values were estimated using the FAO-56 Penman–Monteith method. The results showed that there was a large gap in ETp between different months in the Hancang River Basin, with a trend of first increasing and then decreasing within a year. The highest monthly evapotranspiration was 114.119 mm (July), and the lowest was 42.761 mm (January). The maximum relative humidity index was 0.822 (August), and the minimum was -0.979 (January). The average temperature, precipitation, average relative humidity, and solar radiation are positive factors that affect ETp, while average air pressure is a negative factor that affects ETp. This study provides a reference for the wet conditions of small watersheds and for countermeasures to address climate change.

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confidence: 99%

Analysis of the variation in potential evapotranspiration and surface wet conditions in the Hancang River Basin, China

Zhang

Wang

2021

Sci Rep

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“…However, currently, there is no universal rule for determining how much the perturbation will be added to the parameter. Therefore, in the sensitivity analysis of this study, specifically, the perturbation is β times the value of a meteorological variable, where β is a constant randomly sampled from a uniform distribution (0~20%) 16 . The form of the SC method is as follows:…”

Section: Sensitivity Analysis Methodsmentioning

confidence: 99%

“…Previous studies also showed that the sensitivities of ET0 variations to meteorological factors varied in space and time [34][35][36][37][38][39] . In order to understand the mechanisms of the regional ET0 variations caused by variability in meteorological factors, researchers have studied the sensitivities of ET0 to main meteorological factors using a variety of sensitivity analysis methods in different regions 16,36,38,[40][41][42][43] . However, at present, there is still a lack of systematic research on which meteorological factors have the greatest impact on ET0 in the Zhangye farmland during the last decade at different time scales.…”

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confidence: 99%

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Variations and Sensitivity Analysis of Reference Evapotranspiration During 2010-2019 in the Zhangye Farmland Oasis, Northwest China

Fang¹

2021

Preprint

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Reference evapotranspiration (ET0) is an important parameter for agricultural water management in the arid Zhangye farmland oasis. However, the ET0 variations in this oasis over the last decade and meteorological forcings of these variations are unknown. This study investigated the ET0 variations during 2010-2019 in this oasis using the FAO-56 Penman-Monteith (PM) and Hargreaves equations. Results showed that the ET0 features daily and monthly variations with peak values in mid-July and an annual cycle. Although the estimated ET0 series based on the two equations have high correlations in the time domain, the Hargreaves equation always underestimates the ET0 compared to the PM equation. The yearly ET0 showed statistically significant increasing trends (90% significance level) during 2010-2019, while statistically significant increasing trends in monthly ET0 are found only in March and November. Increasing trends reflected in monthly and yearly ET0 are mainly attributed to the increasing maximum temperature and sunshine duration and decreasing relative humidity. Sensitivity analysis demonstrated that the meteorological factor to which the ET0 is most sensitive varies with time scale and equation. Moreover, regression equations used to correct the underestimation associated with the Hargreaves equation for estimating ET0 in the Zhangye farmland oasis also were constructed.

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“…The detailed algorithm for the other variables can be found in FAO 56 (Allen et al, 1998). This method has been widely used in hydrology, agriculture and climatological studies (Biazar et al, 2019;Dinpashoh et al, 2011Dinpashoh et al, , 2019Jhajharia et al, 2015).…”

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confidence: 99%

A monthly regression correction model for the Hargreaves–Samani method in Mainland China

Xia

Zhu

Pan

et al. 2020

Irrigation and Drainage

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Reference crop evapotranspiration (ET 0) is an important parameter for irrigation engineering. It can be calculated using the Penman-Monteith method (PM), which results in ET 0-PM. This study uses ET 0-PM to determine the availability of a monthly linear regression correction model for the Hargreaves-Samani method (HG). The data were obtained from 647 meteorological stations in mainland China, which are contained within the data set of monthly values of climate data from Chinese surface stations. For most stations, the correlation coefficient of ET 0-PM and ET 0-HG (determined by the HG method) ranges from 0.5 to 1.0. This provides the necessary conditions for the monthly linear regression correction of ET 0-HG. The mean relative change of the mean absolute error before and after the ET 0-HG correction for each year indicates that the scheme adopted in this study yields improved correction results during autumn, winter and spring in mainland China and poor results during summer. However, the monthly regression correction model for the HG is only available for part of the stations in each season. This study supplements a case for the larger-scale ET 0-HG monthly regression correction. This can be a reference for the further refinement of the ET 0-HG spatio-temporal correction K E Y W O R D S reference crop evapotranspiration, Hargreaves-Samani method, linear regression model, Penman-Monteith method, mainland China Résumé L'évapotranspiration des cultures de référence (ET 0) est un paramètre important pour l'ingénierie de l'irrigation. ET 0 peut être calculé à l'aide de la méthode Penman-Monteith (PM), qui donne ET 0-PM. Cette étude utilise ET 0-PM pour déterminer la disponibilité d'un modèle de correction de régression linéaire mensuel pour la méthode Hargreaves-Samani (HG). Les données ont été obtenues de 647 stations météorologiques en Chine continentale, qui sont contenues dans l'ensemble de données des valeurs mensuelles des données climatiques des stations de surface chinoises. Pour la plupart des stations, le coefficient de corrélation ET 0-PM et ET 0-HG (déterminé par la méthode HG) *Un modèle de correction de régression mensuelle pour la méthode Hargreaves-Samani en Chine continentale.

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Sensitivity analysis of the reference crop evapotranspiration in a humid region

Cited by 37 publications

References 42 publications

Analysis of the variation in potential evapotranspiration and surface wet conditions in the Hancang River Basin, China

Analysis of the variation in potential evapotranspiration and surface wet conditions in the Hancang River Basin, China

Variations and Sensitivity Analysis of Reference Evapotranspiration During 2010-2019 in the Zhangye Farmland Oasis, Northwest China

A monthly regression correction model for the Hargreaves–Samani method in Mainland China

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