Accurate evapotranspiration, ET, data are crucial for irrigation management projects, especially in drought prone regions. Evapotranspiration rates can be estimated by micrometeorological methods and the energy balance equation, soil depletion techniques, mass exchange methods, or by using weighting lysimeters. These methods usually are expensive, difficult to operate, and some of them present problems for measurements in heterogeneous vegetation. Therefore, the search for accurate methods for estimating ET fluxes using low-cost, transportable and robust instrumentations is a subject of interest. The eddy covariance (EC) method is the commonly used micrometeorological technique providing direct measurements of latent heat flux (or evapotranspiration). It adopts a sonic anemometer to measure high-frequency vertical wind speed fluctuations about the mean and an infrared gas analyzer to measure high frequency water concentration fluctuations. These fluctuations are paired to determine the mean covariance of the wind speed and humidity fluctuations about the mean to directly estimate latent heat flux (LE). In the EC method, the sensible heat flux is also estimated using the covariance of the fluctuation in vertical wind speed and variations in temperature about their means. While the preferred method for measuring turbulent fluxes is the eddy covariance (EC) method, the lack of closure is unresolved and a full guidance on experimental set up and raw data processing is still unavailable. Other energy balance approaches, such as the Bowen ratio and aerodynamic methods, have a sound theoretical basis and can be highly accurate for some surfaces under acceptable conditions. Biometeorological measurements and theory identified large, organized eddies embedded in turbulent flow, called “coherent structures” as the entities which exchange water vapour, heat, and other scalars between the atmosphere and plant communities. Based on these studies, a new method for estimating scalar fluxes called “Surface Renewal (SR)” was proposed by Paw U and Brunet (1991). Surface Renewal (SR) theory in conjunction with the analysis of the observed ramp-like patterns in the scalar traces provides an advantageous method for estimating the surface flux density of a scalar. The method was tested with air temperature data recorded over various crop canopies. Results of the studies (Snyder et al., 1996; Spano et al., 1997; Consoli et al., 2006; Castellvi et al., 2008) have demonstrated good SR performance in terms of flux densities estimation, well correlated with EC measurements. The approach has the advantages to (i) require as input