Evaluation of energy balance, combination, and complementary schemes for estimation of evaporation.

A comparison between three basic techniques for estimation of actual evapotranspiration, namely: the Energy Balance, the Combination, and the Complementary approaches, is undertaken. We utilize Monin- Obukhov Similarity Theory (MOST) as a framework for the energy balance method, the single-layer Penman- Monteith method for the combination approach, and the Advection-Aridity method as the complementary approach. Data from three flux tower stations are used to evaluate model estimated heat fluxes at short time steps. The results indicate advantages and/or limitations of each method under different conditions, highlighting issues in application of the Advection-Aridity technique in dry conditions and energy balance methods over sparse canopies.

Figure 1: Scatter plots of observed versus estimated latent heat flux using EB, PM, and AA methods.