Radiometric Accuracy of Mipas Calibrated Spectra

A precise radiometric calibration of the measured spectra is essential for a good quality of the trace gas retrievals. In order to ensure a high radiometric accuracy, a calibration scenario has to be developed that meets the tradeoff between data quality and the necessary measurement time. Furthermore the radiometric calibration requires an accurate instrument characterisation. This presentation will discuss the instrument behaviour, especially the radiometric stability. Furthermore, systematic differences between measurements in different sweep directions of the interferometer will be addressed. These effects have been carefully analysed, and under nominal conditions, they do not have a significant impact on the quality of the retrieved trace gas profiles. Another crucial issue that will be discussed is the detector non-linearity, which needs to be characterised precisely in order to be properly corrected. A comparison between on-ground and in-flight characterisation measurements has shown a generally good agreement.