A Dual-Temperature-Difference Approach to Estimate Daytime Sensible and Latent Heat Fluxes Under Advective Conditions During BEAREX08.

The Dual-Temperature-Difference (DTD) approach uses continuous radiometric surface temperature measurements in a two-source (soil + vegetation) energy balance model to solve for the daytime evolution of the sensible and latent heat fluxes.  By using the surface-air temperature difference at two times during the day, the errors associated with accurate absolute surface-air temperature differences when the two-source model is applied for a single time-of-day are reduced.  The DTD approach is useful in areas with significant local variations in air temperatures such as in advective environments with irrigated and non-irrigated fields.  The DTD approach is evaluated at several sites ranging from irrigated and dryland cotton crops to a grassland/rangeland site.