Evaluation of FAO-56 Penman-Monteith Model Using Alternative Climatic Data Application to Afghanistan

Abstract The Penman-Monteith model with alternative and measured data in three regions of Afghanistan (Central-North- East) was discussed by estimating reference evapotranspiration (ET0). The result showed that in the high rate of ET0, the difference between ET0 that estimated using alternative and measured data could be more than 2 mm day-1 when using alternative humidity and wind data in the Central region. Because there is a windy season in the Central region only, the results seem to mean that one of the cases, the impact of the windy season on the Penman-Monteith model, has been found. The alternative solar radiation was effective in any region.