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Table 2

Model variables/parameter descriptions

ModelParameterReference
Blaney–Criddle a, b: climatic coefficients P: mean daily percentage of total annual daytime hours T: daily mean air temperature (°C) n/N: mean ratio of actual to possible sunshine hours Ud: day time (7 A.M.–7 P.M.) wind speed at 2 m RHmin: minimum daily relative humidity ETo: reference evapotranspiration (mm day−1Doorenbos & Pruitt (1977)  
Penman–Monteith Δ: slope of the vapor pressure curve (kPa °C−1) Rn: net radiation (MJ m−2 day−1) G: soil heat flux density (MJ m−2 day−1) U2: wind speed at 2 m height (m s−1) es: saturation vapor pressure (kPa) ea: actual vapor pressure (kPa) (esea): saturation vapor pressure deficit (kPa) T: mean daily air temperature at 2 m height (°C) : psychrometric constant (kPa °C−1Allen et al. (1998)  
Hargreaves–Samani Ra: extraterrestrial radiation (MJ m−2 day−1) Tmin: minimum temperature (°C) Tmax: maximum temperature (°C) Hargreaves & Samani (1985)  
Irmak Rs: solar radiation (MJ m−2 day−1) T: mean daily temperature (°C) RH: daily mean relative humidity (%) Irmak et al. (2003)  
Priestley Rn: net radiation (MJ m−2 day−1) λ: latent heat of vaporization (MJ kg−1) Δ: slope of the vapor pressure curve (kPa °C−1) α = 1.25 : psychrometric constant (kPa °C−1Priestley & Taylor (1972) 
Turc Rs: solar radiation (MJ m−2 day−1) T: daily mean air temperature (°C) RH: daily mean relative humidity (%) Turc (1961) 
Thornthwaite im: thermal index Tm: mean air temperature (°C) α: coefficient M: correction factor Thornthwaite (1948) 
Jensen–Hayes Rs: solar radiation (MJ m−2 day−1) T: daily mean air temperature (°C) CT: temperature constant CT = 0.25, Tx = −3 Jensen & Haise (1963)  
ModelParameterReference
Blaney–Criddle a, b: climatic coefficients P: mean daily percentage of total annual daytime hours T: daily mean air temperature (°C) n/N: mean ratio of actual to possible sunshine hours Ud: day time (7 A.M.–7 P.M.) wind speed at 2 m RHmin: minimum daily relative humidity ETo: reference evapotranspiration (mm day−1Doorenbos & Pruitt (1977)  
Penman–Monteith Δ: slope of the vapor pressure curve (kPa °C−1) Rn: net radiation (MJ m−2 day−1) G: soil heat flux density (MJ m−2 day−1) U2: wind speed at 2 m height (m s−1) es: saturation vapor pressure (kPa) ea: actual vapor pressure (kPa) (esea): saturation vapor pressure deficit (kPa) T: mean daily air temperature at 2 m height (°C) : psychrometric constant (kPa °C−1Allen et al. (1998)  
Hargreaves–Samani Ra: extraterrestrial radiation (MJ m−2 day−1) Tmin: minimum temperature (°C) Tmax: maximum temperature (°C) Hargreaves & Samani (1985)  
Irmak Rs: solar radiation (MJ m−2 day−1) T: mean daily temperature (°C) RH: daily mean relative humidity (%) Irmak et al. (2003)  
Priestley Rn: net radiation (MJ m−2 day−1) λ: latent heat of vaporization (MJ kg−1) Δ: slope of the vapor pressure curve (kPa °C−1) α = 1.25 : psychrometric constant (kPa °C−1Priestley & Taylor (1972) 
Turc Rs: solar radiation (MJ m−2 day−1) T: daily mean air temperature (°C) RH: daily mean relative humidity (%) Turc (1961) 
Thornthwaite im: thermal index Tm: mean air temperature (°C) α: coefficient M: correction factor Thornthwaite (1948) 
Jensen–Hayes Rs: solar radiation (MJ m−2 day−1) T: daily mean air temperature (°C) CT: temperature constant CT = 0.25, Tx = −3 Jensen & Haise (1963)  
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