An intercomparison of regional latent heat flux estimation using remote sensing data

The aerodynamic resistance energy balance residual method is widely used for surface latent heat flux estimation. In this study, we examine the theoretical background and implementation details of this methodology with respect to remote sensing data applications. The residual method requires estimation of aerodynamic resistance to heat transfer that necessitates the measurements of several ground-based observations including land surface vegetation height and surface wind speed. Consequently, it becomes very difficult to implement this method over large areas. A simple scheme is proposed for the distributed estimation of surface latent heat flux based on an interpretation of the triangle (or trapezoid) space of remotely sensed vegetation index and radiometric surface temperature. Two case studies using realistic remote sensing data over the southern Great Plains in the United States are presented to demonstrate the performance of both methods. Results suggest that the proposed method can achieve similar or better estimation of latent heat flux over large areas. The proposed method is well suited for distributed estimation of latent heat flux while the commonly used residual method is appropriate for site-specific estimation if detailed surface information is available.