Mohadese Sadat Fakhar - Water Sciences and Engineering, Faculty of Agricultural and Natural Resources, ImamKhomeini International y of Agricultural and Natural Resources, Imam KhomeiniInternational University, Qazvin, Iran
Abbas Kaviani - Associate professor, Department of Water Sciences and Engineering, Imam KhomeiniInternational University,Qazvin, Qazvin, Iran

Evaluation of evapotranspiration in an area in order to make optimal use of water resources is one of the major issues in water management of the country. The equations used to calculate evapotranspiration do not use the same climatic parameters and, due to their experimental nature, are not suitable for all climatic conditions. Potential evapotranspiration and reference evapotranspiration are different in concepts, equations, and contexts; however, many researchers have considered the use of the two terms to be the same. This study comprehensively examined the ETp and ETo equations. In addition, a number of equations based on temperature and radiation methods were investigated, which showed that the temperature method had the best estimate in the study area

Meteorological parameters; Radiation Method; Temperature Method