Procedures Used for Airborne Measurements of Upwelling Infrared Radiation

We analyze the errors of airborne radiometric measurements of the infrared upwelling radiation I _x of the surface performed using conventional and modified procedures (with calibrators in the form of flat reflecting mirror-like surfaces oriented to reflect the measured radiation I _x to the radiometer in the process of calibration) for the modes of operation of a radiometer with and without thermostatic control. We propose relations for finding I _x as well as for the instrumental and procedural errors and give recommendations for their reduction. It is shown that the modified procedure leads to smaller errors than the conventional procedure.