Utility of the thermal-based Dual-Temperature-Difference technique under strongly advective conditions during BEAREX08

摘要

Application of most thermal remote sensing-based energy balance models requires meteorological inputs of wind speed and air temperature. These are typically obtained from the nearest weather station which is often situated in a non-ideal location having limited fetch. In addition, the uncertainty of surface temperature estimates can be several degrees due to sensor calibration issues, atmospheric effects and variation in surface emissivity. The Dual-Temperature-Difference (DTD) method, which was derived from the Two-Source Model (TSM) of Norman et al. (1995), uses a double difference of the time rate of change in radiometric and air temperature observations, and was developed to reduce errors associated with deriving the temperature gradient in complex landscapes, such as agricultural environments having a patchwork of irrigated and non-irrigated fields. The scheme is relatively simple, requiring minimal ground-based data and meteorological input from an existing synoptic weather station network. The utility of this scheme was tested with ground-based radiometric temperature observations from the Bushland Evapotranspiration and Agricultural Remote Sensing Experiment 2008 (BEAREX08), conducted in the semi-arid climate of the Texas High Plains.