Lakhasly

Potential evapotranspiration is an important input for simulations of the hydrological cycle.Deficit and wind velocity (Singh et al., 1997).In 2000, Xu and Singh compared eight energy methods, including the ones described By Turc (1961), Makkink (1957), Jensen and Haise (1963), Hargreaves (1975), and Doorenbos

And Pruitt (1977), Bordne and McGuinness (1972), Abtew (1996) and Priestley and Taylor

(2005).Xu et al. ana have combined seven types of temperature-based methods in 2001; the results show that the Blaney-Criddle Method, Hargreaves method and Thornthwaite method have better results for simulation

Beyond the others.He found that: the application of the Penman-Monteith method, Makkink, Priestley and Taylor and Abtew were better than the other methods Many researchers have proposed some temperature-based methods under limited climate data conditions.The effect was analysed in 1997 by Gardelin and Lindstrom

Different possible methods for calculating the evapotranspiration on simulation accuracy

The Model HBV.They found that the Penman process, corrected with temperature, improved the Precise simulation; nevertheless, the results obtained with the Priestley-Taylor method Had been better.The possible methods for estimating evapotranspiration can be divided into the energy-based methods,

Methods based on temperature and mass transfer, depending upon their mechanisms The energy-based approach uses the principle of energy balance to estimate future evapotranspiration.(1972).

Potential evapotranspiration is an important input for simulations of the hydrological cycle.
There are many possible methods for estimating evapotranspiration; however, the use is
Simulation accuracy of a given hydrological model is affected by various methods for estimating possible evapotranspiration. The effect was analysed in 1997 by Gardelin and Lindstrom

Different possible methods for calculating the evapotranspiration on simulation accuracy

The Model HBV. They found that the Penman process, corrected with temperature, improved the
Precise simulation; nevertheless, the results obtained with the Priestley-Taylor method
Had been better. Consequently , the best method was the Priestley-Taylor method, which, by considering the soil heat flux, proved the negative potential evapotranspiration in winter.

The possible methods for estimating evapotranspiration can be divided into the energy-based methods,

Methods based on temperature and mass transfer, depending upon their mechanisms
The energy-based approach uses the principle of energy balance to estimate future evapotranspiration. In 2000, Xu and Singh compared eight energy methods, including the ones described
By Turc (1961), Makkink (1957), Jensen and Haise (1963), Hargreaves (1975), and Doorenbos

And Pruitt (1977), Bordne and McGuinness (1972), Abtew (1996) and Priestley and Taylor

(2005). (1972). He found that: the application of the Penman-Monteith method, Makkink, Priestley and Taylor and Abtew were better than the other methods Many researchers have proposed some temperature-based methods under limited climate data conditions. Xu et al. ana have combined seven types of temperature-based methods in 2001; the results show that the Blaney-Criddle
Method, Hargreaves method and Thornthwaite method have better results for simulation

Beyond the others. The mass transfer-based method is one of the oldest, which mainly considers the effect of air pressure on the free water surface.
Deficit and wind velocity (Singh et al., 1997). In 1802 Dalton developed the first method for estimating potential evaporation, while in 1948 Penman presented his approach on the basis of
Principles of mass transit.