Uncertainties in latent heat flux measurement and estimation: implications for using a simplified approach with remote sensing data

Abstract

Accurate estimation of surface energy fluxes is essential for various hydrological, meteorological, agricultural, and ecological applications. Over the years, a wide variety of instrument systems and estimation methodologies have been developed to measure and estimate surface fluxes. Comparisons of various scale field experimental data and different model estimates show a large degree of scatter with a wide range of root mean square error. We explore and evaluate analytically the error property of the traditionally used energy balance residual method for latent heat flux estimation in an attempt to identify the possible existence of an irreducible error bound for latent heat flux measurement and estimation over large areas. Our analysis shows that the error is typically on the order of 10%–20% or larger for surface sensible and latent heat fluxes. A simplified remote sensing latent heat flux estimation approach is proposed and its error properties are evaluated. Results suggest that a similar or better error bound can be achieved using primarily remotely sensed data over large areas for the estimation of latent heat flux using this alternative approach.