Sensitivity Analysis of the Penman-Monteith reference Crop Evapotranspiration to Climatic Variables in Iran

Sharifi, Abdolkarim; Dinpashoh, Yagob

doi:10.1007/s11269-014-0813-x

Cited by 62 publications

(38 citation statements)

References 19 publications

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“…In the sensitivity curve approach (McKenney and Rosenberg 1993;Singh and Xu 1997;Goyal 2004), the degree of sensitivity is represented by the slope and the linearity of the curve, while the curve is drawn between the relative change of the climate factor and the relative change of ET 0 . Sensitivity curves of ET 0 to climatic variables are generally linear (Sharifi and Dinpashoh 2014). The sensitivity coefficient approach was proposed by McCuen (1974) in which the sensitivity coefficient was mathematically defined as a dimensionless variable to describe the effects of the changes in the climate variables on ET.…”

Section: Methods For Sensitivity Analysismentioning

confidence: 99%

“…This indicates that the sensitivity of ET 0 varies significantly to the climate variables in different regions and different climate characteristics. Sharifi and Dinpashoh (2014) have found that ET 0 is more sensitive to the average temperature in summer. Maximum temperature is the most sensitive variable in Bushland, Scottsbluff, and Twitchell in the USA while maximum temperature and solar radiation are the most sensitive factors in Clay in central USA (Irmak et al 2006).…”

Section: Characteristics and Trends Of The Changes Of Climate Variablmentioning

confidence: 97%

“…Therefore, the sensitivity of ET to the climatic factors is an important research area in hydrology. Such studies have important theoretical and practical values to better understand the effects of climate on regional hydrologic cycle and agricultural irrigation management (Gao et al 2006;Irmak et al 2006;Sharifi and Dinpashoh 2014).…”

Section: Introductionmentioning

confidence: 99%

“…Results have shown that the sensitivity of ET 0 to wind speed and air temperature decreased from arid to humid climate, whereas its sensitivity to sunshine duration increased from arid to humid environment. Sharifi and Dinpashoh (2014) have analyzed the sensitivity of ET 0 to the average temperature, vapor pressure, wind speed, and net radiation in the arid and semi-arid Iran region and concluded that average temperature is the most sensitive climate factor and vapor pressure is the least sensitive factor in the year scale. The research areas should be differentiated into different climate types with consideration of substrate characteristics during the evapotranspiration studies, and both regional difference and seasonal difference should be investigated.…”

Section: Introductionmentioning

confidence: 99%

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Sensitivity study of reference crop evapotranspiration during growing season in the West Liao River basin, China

Gao

Dong

et al. 2015

Theor Appl Climatol

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We have analyzed the trends of reference crop evapotranspiration (ET 0 ) through the Penman-Monteith model and climate factors in the West Liao River basin using the Mann-Kendall test after removing the effect of significant lag-1 serial correlation from the time series of the data by trendfree pre-whitening. The changing characteristics of the sensitivity coefficients and the spatial distribution during growing season are investigated, and the correlation between the sensitivity coefficients with elevation and the key climate factors by relative contribution and stepwise regression methods are evaluated. A significant overall increase in air temperature, and a significant decrease in wind speed, solar radiation, sunshine duration, relative humidity, and a slight decrease in ET 0 are observed. Sensitivity analysis shows that ET 0 is most sensitive to solar radiation, followed by relative humidity. In contrast, ET 0 is least sensitive to the average air temperature. The sensitivity coefficients for the maximum and minimum air temperature and relative humidity have a significant negative correlation with elevation, while the coefficients for other variables are not strongly correlated with elevation. The spatial distribution of the sensitivity coefficients for wind speed and solar radiation is opposite, i.e., in regions where the sensitivity coefficients for wind speed are high; the sensitivity coefficients for solar radiation are low and vice versa. The sensitivity for relative humidity and average air temperature is region specific in the plain area. However, ET 0 is most sensitive to the climate change in regions of high elevation. Wind speed is the most dominant contributor followed by solar radiation. Average air temperature contributes the least. The stepwise regression analysis indicates that wind speed is the foremost dominant variable influencing ET 0 . Relative contribution and stepwise regression analysis can be used to determine the main variables affecting ET 0 , and it also strongly supports that the aerodynamic component is the dominant factor.

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Section: Methods For Sensitivity Analysismentioning

confidence: 99%

Section: Characteristics and Trends Of The Changes Of Climate Variablmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Sensitivity study of reference crop evapotranspiration during growing season in the West Liao River basin, China

Gao

Dong

et al. 2015

Theor Appl Climatol

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“…Many evaporation models have been used for calculating evaporation such as the Penman formula (Yang et al 2010;Shen et al 2013;Sharifi and Dinpashoh 2014;Zhang et al 2014), Dalton model (Armstrong et al 2008) and energy balance equations (Li et al 2013b). Previous studies focused on changes in evaporation at different spatial and temporal scales in arid regions, using evaporation models (Li et al 2013a, b;Zhang et al 2014;Zhao and Zhao 2014a, b).…”

Section: Introductionmentioning

confidence: 99%

Evaluating the best evaporation estimate model for free water surface evaporation in hyper-arid regions: a case study in the Ejina basin, northwest China

Pan

et al. 2016

Environ Earth Sci

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Free water surface evaporation is an important process in the hydrologic and energy cycle. Accurate calculation of free water evaporation helps in evaluating the reliability of data on the distribution and quantity of water resources. However, the applicability of evaporation models to the calculation of free water surface evaporation in hyper-arid regions is still uncertain. Moreover, the accuracy of previously used evaporation models should be evaluated for hyper-arid regions. In this study, the Ejina basin in the hyper-arid region of northwest China was selected to address this issue. Measured meteorological data (1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008) were used to calculate free water surface evaporation using the Dalton model, Penman formula, and energy balance equations. Results from two different Dalton models were higher and lower than the results from E 601 pan evaporation, respectively. Results from the Penman formula were lower than results from E 601 pan, whereas results from the energy balance equations are higher than the results from E 601 pan. The results indicate that previous evaporation models are not suited for calculating free water surface evaporation in hyper-arid regions if not modified. Using meteorological data and radiation data (1993)(1994)(1995)(1996)(1997)(1998)(1999)(2000), the Dalton model, energy balance equations, and Penman formula were modified to calculate free water surface evaporation for [2001][2002][2003][2004][2005][2006][2007][2008]. The average annual evaporation from the three modified models was slightly lower than the evaporation from E 601 pan during [2001][2002][2003][2004][2005][2006][2007][2008]. However, the errors in the values were only 11-14 mm, which were much lower than in previous models. The modified Dalton model and Penman formula yielded a higher accuracy of the calculation, whereas the modified energy balance equations had the lowest accuracy.

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Assessment of reference evapotranspiration across an arid urban environment having poor data monitoring system

Shafieiyoun

Gheysari

Khiadani

et al. 2020

Hydrological Processes

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Estimation of reference evapotranspiration (ET0) in urban areas is challenging but essential in arid urban climates. To evaluate ET0 in an urban environment and non‐urban areas, air temperature and relative humidity were measured at five different sites across the arid city of Isfahan, Iran, over 4 years. Wind speed and sunshine hours were obtained from an urban surrounding weather station over the same period and used to estimate ET0. Calculated ET0 was compared with satellite‐based ET0 retrieved from the MOD16A2 PET product. Although MODIS PET was strongly correlated with the Valiantzas equation, it overestimated ET0 and showed average accuracy (r = 0.93–0.94, RMSE = 1.18–1.28 mm/day, MBE = 0.73–0.84 mm/day). The highest ET0 differences between an urban green space and a non‐urban area were 1.1 and 0.87 mm/day, which were estimated by ground measurements and MODIS PET, respectively. The sensitivity of ET0 to wind speed and sunshine hours indicated a significant effect on cumulative ET0 at urban sites compared to the non‐urban site, which has a considerable impact on the amount of irrigation required in those areas. Although MODIS PET requires improvement to accurately reflect field level microclimate conditions affecting ET0, it is beneficial to hydrological applications and water resource managers especially in areas where data is limited. In addition, our results indicated that using limited data methods or meteorological data from regional weather stations, leads to incorrect estimation of ET0 in urban areas. Therefore, decision‐makers and urban planners should consider the importance of precisely estimating ET0 to optimize management of urban green space irrigation, especially in arid and semi‐arid climates such as the city of Isfahan.

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Sensitivity Analysis of the Penman-Monteith reference Crop Evapotranspiration to Climatic Variables in Iran

Cited by 62 publications

References 19 publications

Sensitivity study of reference crop evapotranspiration during growing season in the West Liao River basin, China

Sensitivity study of reference crop evapotranspiration during growing season in the West Liao River basin, China

Evaluating the best evaporation estimate model for free water surface evaporation in hyper-arid regions: a case study in the Ejina basin, northwest China

Assessment of reference evapotranspiration across an arid urban environment having poor data monitoring system

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