Deriving soil and vegetation temperatures of a dynamically developing maize field from ground thermal images recorded during the HiWATER-MUSOEXE

Thermal cameras are helpful instruments for measuring surface temperatures in field experiments. However, previous studies haven´t detailed the method of deriving component temperatures of vegetation and soil over heterogeneous surfaces. In addition, the sources contributing to uncertainties in the derived component temperatures require further investigation. We present a study wherein the component temperatures of a dynamically developing maize field were derived from thermal images. The sources influencing the derived component temperatures have been investigated and different parameterization schemes for atmospheric downwelling radiation have been compared. The results demonstrate that the thermal cameras provide a feasible method of deriving the component temperatures. If the thermal camera is mounted at approximately 30 m above the target and then the atmospheric upwelling radiation and transmittance is ignored, a 1.0-2.0 K error for the component temperatures may occur.