The Use of Micrometeorological Data to Identify Significant Variables in Evapotranspiration Modeling

Because of the crucial role that plays in the hydrological water balance, evapotranspiration estimation has always represented a field of substantial and con inuous scientific application. Evapotranspiration fluxes are however and objectively difficult to be measured and predicted. Many different models have then been reported in the related literature, which are able to quantify the evapotranspiration process starting from a more or less reduced database of empirical data. The present paper aim at the comparison between models of maximum crop and actua evapotranspiration (ET0) applied to an e dy covariance micrometeorological tower located in Southern Italy. In particular, the Penman-Monteith model, in the simplified version proposal of FAO, and the model of Priestley- Taylor, have been herein considered. On a daily time scale of aggregation, both examined models have good capacity in the estimation of evapotranspiration fluxes. Using a database input of daily average air temperatures and analytically calculating the other relevant parameters, both the simplified method proposed by FAO Penman- Monteithand the Pristley-Taylor model show a comparable fit to the observed data, wi h a similar over-prediction of about respectively 17% and 14%.