Estimation of Potential Evaporationspiration in Different Climates of Iran

There are different models for estimation of evaporationspiration that are based on humidity, radiation, temperature and compound groups. The main purpose of this study is to calibrate the evaporationspiration methods and to select the best one for different climatical conditions in provinces of Iran. Meteorological data were collected from 10 synoptic stations in provinces of Iran. The comparison among the potential evaporationspiration, calculated based on the available four experimental groups and observational lysimeter data, for selection of the best model showed that the Hargreaves-Samani method (1985) with R2< 0.94 and RMSE < 1mm/day was the superior one in the proposed seven provinces and was identified as the best method in the provinces with dry and semi-arid climate. While, the humid methods showed proper results in central provinces and Caspian Sea basin (with moderate and humid climate) and Albrecht (1950) method was selected as the best method among them in these provinces.