Models for assessment of actual evapotranspiration from remote sensing: theoretical basis

In the evaluation of the onset, severity and duration of situations of water stress and droughts, indicators based on processes with intensive use of remote sensing can be used. In the monitoring of agricultural activities as well as the management of water and forest resources, spatio-temporal distributions of information of actual evapotranspiration (ETact) are crucial. This work presents the theoretical aspects of spatio- temporal assessment of ETact process, from remote sensing and meteorological data.