A method to retrieve blackbody temperature errors in the two points radiometric calibration

Measurements of the atmospheric thermal emission using an infrared Fourier transform spectrometer need to be radiometrically calibrated. As for several existing instruments (IASI-MetOp, IASI-balloon, NAST-I, AERI, etc.), the two points radiometric calibration is generally performed using two well-characterized blackbodies at two different temperatures (or one blackbody and the cold space), which allow to determine the response and the self-emission of the instrument. To perform an accurate radiometric calibration, the emissivity and the temperature of each blackbody should be known accurately. The blackbody temperatures are chosen to fit the characteristics of the instrument. The measurement of these temperatures is essential. This paper proposes a method to perform an accurate radiometric calibration even when one of the two blackbodies temperatures is not perfectly measured, by numerically retrieving this erroneous temperature.