Relationships among Remotely Sensed Data, Surface Energy Balance, and Area-Averaged Fluxes over Partially Vegetated Land Surfaces

Abstract Numerous recent field experiments have examined the use of remote sensing to estimate land surface fluxes of latent and sensible heat using combinations of thermal, visible, and near-infrared data. While substantial progress has been made, significant problems remain unresolved with respect to both spatial aggregation of land surface fluxes over heterogeneous land surfaces and the use of thermal data for estimating sensible heat fluxes. In this paper a surface energy balance model is used, in association with remotely sensed and in situ data, to examine issues of measurement, scaling, and aggregation of high-frequency spatial variation in land surface properties and fluxes over regional scales. Results from this analysis show that instantaneous land surface fluxes modeled from high spatial resolution remotely sensed data may be estimated only approximately. Comparisons between modeled versus observed fluxes averaged over regional scales (≈225 km2), on the other hand, exhibit excellent agreement. ...