Estimation of potential evapotranspiration in Al-Hassa oasis,Saudi Arabia

An accurate estimation of the potential evapotranspiration can be achieved ba applying empirical evapotranspiration coefficients which are determined under Al-Hassa prevailing climatic conditions. Correlation coefficient results indicate that most of the climatological variables have a strong relationship with potential evapotranspiration except wind speed and precipition variables which have a weak relationship. Multiple regression results also indicate that there is a significant effect of some of the climatologiecal variables in the potential evatranspiration and there is no significant effect of the others at the significant level of 0.05. The results of the stepwise regression indicate that evaporation class “A” pan, air temperature, sunshine hours, radiation, relative humidity, and wind speed variables have a significant effect at the significant level of 0.05 on the overall mean monthly potential evapotranspiration of the Blaney-Criddle, Pan Evaporation, and Jensen-Haise, therefore, the equation which has developed for estimating potential evapotranspiration in Al-Hassa is based on these six variables (evaporation class “A” pan, air temperature, sunshine hours, radiation, relative humidity, and wind speed).