Solar and Net Radiation-Based Equations to Estimate Reference Evapotranspiration in Humid Climates

Irmak, Suat; Irmak, A.; Allen, Richard G.; Jones, James W.

doi:10.1061/(asce)0733-9437(2003)129:5(336)

Cited by 243 publications

(102 citation statements)

References 23 publications

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“…Nandagiri and Kovoor (2006) evaluated the performance of seven different empirical methods for the determination of ETo under different climatic conditions in India, and they reported that the empirical equation of Turc is the best option under humid conditions. Tabari et al (2013) compared 31 different ETo equations, including two new radiometric equations they developed (similar to the work of Irmak et al 2003) in the north of Iran (in a humid environment), considering the PM-FAO56 equation as the standard. The results revealed that the developed equation performed better than the other equations selected.…”

Section: Introductionmentioning

confidence: 99%

Three decades of reference evapotranspiration estimates for a tropical watershed in the eastern Amazon

Júnior

Souza

Tavares

et al. 2017

An. Acad. Bras. Ciênc.

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This study estimated the reference evapotranspiration rate (ETo) for the Itacaiúnas River Watershed (IRW), Eastern Amazonia, and measured the accuracy of eight empirical equations: Penman-Monteith (PM), Priestley-Taylor (PT), Hargreaves and Samani (HS), Camargo (CAM), Thornthwaite (TH), Hamon (HM), Kharrufa (KF) and Turc (TC) using monthly data from 1980 to 2013. In addition, it verifies the regional applicability to the IRW using a for the Marabá-PA station. The methods TC and PM (FAO56) presented the best results, which demonstrate that radiation and higher temperatures are the dominant drivers in the Evapotranspiration process, while relative humidity and wind speed have a much smaller impact. The temporal and spatial variability of ETo for IRW show has strong seasonality, increasing during the dry season and decreasing during the rainy season. The statistical analyses at 1% level of significance, indicates that there is no correlation of the residuals between the dry and rainy seasons, and test of the physical parameters such as mean temperature, solar radiation and relative air humidity explains the variations of ETo.

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Section: Introductionmentioning

confidence: 99%

Three decades of reference evapotranspiration estimates for a tropical watershed in the eastern Amazon

Júnior

Souza

Tavares

et al. 2017

An. Acad. Bras. Ciênc.

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“…The Penman-Monteith method was simplified by Irmak et al (2003) as expressing a multi-linear regression function that only net radiation ( ) and solar radiation ( ) are needed as requires input parameters for estimation [9] Eq. (2) and (3).…”

Section: Introductionmentioning

confidence: 99%

Re- Examining the Validity of Referece Evapotranspiration Estimation in Herat, Afghanistan

Ganji¹

2017

Geomate

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ABSTRACT:The aim of this study is to contribute in irrigation scheduling by proposing adaptable models that are widely used for the estimation of reference evapotranspiration ( 0 ) in Herat, Afghanistan. Six well-known models, The Penman-Monteith ( 0 ), Hargreaves ( 0 ), Hamon ( 0 ), Thornthwaite ( 0 ), solar radiation based ( 0 ) and Net radiation based ( 0 ) were compared, and the pan evapotranspiration � � model was used as indicator. The pan coefficient ( ) proposed by Pereira was used to convert pan evaporation ( ) to . Results obtained showed that, the 0 values estimated by all the methods were shown to be close to those of in the second period (spring, fall and winter). However, large differences emerged in the first period (the windy summer), with the exception of 0 . This method displayed a small difference only in June and July. Pearson's correlation ( ) showed that the estimates produced by all the simpler methods were significant correlated with those of in the second period, but weakly correlated in the first period. The 0 method produced the lowest value of 1.3 mm day -1 , based on the standard error estimation ( ). The seasonally-based average difference between and 0 was smaller than that of the other methods in the first period, at 1.9 mm day -1 . The 0 estimation rate was therefore closest to . It is concluded that the methods that used wind factor are more adaptable than those not used wind factor especially in Herat, Afghanistan. The wind might be the reason of the differences between and 0 in the windy summer.

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“…Previous research has estimated extinction depth in a variety of soil types [16][17][18][19]. The grain size characteristics of the soil or sediment, position of the water table, and climate are known to affect the extinction depth as demonstrated in actual measurements [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

“…The grain size characteristics of the soil or sediment, position of the water table, and climate are known to affect the extinction depth as demonstrated in actual measurements [20][21][22]. Commonly, estimates of extinction depth research have been conducted considering total evapotranspiration without a separation of diffusive evaporation loss and plant impacts via transpiration [16][17][18][19]. Furthermore, Soylu et al [23] used different numerical models to investigate the sensitivity of land surface evapotranspiration to water table depth and soil texture.…”

Section: Introductionmentioning

confidence: 99%

Experimental Measurement of Diffusive Extinction Depth and Soil Moisture Gradients in a Dune Sand Aquifer in Western Saudi Arabia: Assessment of Evaporation Loss for Design of an MAR System

Mughal

Jadoon

Martin

et al. 2015

Water

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A component of designing a managed aquifer recharge system in a dune aquifer is the control of diffusive evaporative loss of water which is governed by the physical properties of the sediments and the position of the water table. A critical water table position is the "extinction depth", below which no further loss of water occurs via diffusion. Field experiments were conducted to measure the extinction depth of sediments taken from a typical dune field in the region. The soil grain size characteristics, laboratory porosity, and saturated hydraulic conductivity were measured. The sand is classified as well-sorted, very fine sand with a mean grain diameter of 0.15 mm. Soil moisture gradients and diffusion loss rates were measured using sensors in a non-weighing lysimeter that was placed below land surface. The sand was saturated carefully with water from the bottom to the top and was exposed to the natural climate for a period of about two months. The moisture gradient showed a gradual decline during measurement until extinction depth was reached at about 100 cm below surface after 56 days. Diurnal temperature changes were observed in the upper 75 cm of the column and were negligible at greater depth.

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Solar and Net Radiation-Based Equations to Estimate Reference Evapotranspiration in Humid Climates

Cited by 243 publications

References 23 publications

Three decades of reference evapotranspiration estimates for a tropical watershed in the eastern Amazon

Three decades of reference evapotranspiration estimates for a tropical watershed in the eastern Amazon

Re- Examining the Validity of Referece Evapotranspiration Estimation in Herat, Afghanistan

Experimental Measurement of Diffusive Extinction Depth and Soil Moisture Gradients in a Dune Sand Aquifer in Western Saudi Arabia: Assessment of Evaporation Loss for Design of an MAR System

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