Langley – Ratio calibration method

A new method for transferring calibration from reference to field photometers has been developed within the TestBed and EURAMET EMPIR-MAPP (Metrology for aerosol optical properties) project. This method addresses the case where the two instruments have different spectral bands. The effectiveness of this new method has been demonstrated in a study conducted by Almansa et al. (2023)

The study focused on transferring the calibration from reference instruments, which were calibrated using Langley calibration at Izaña, to field instruments in the case of  significant difference between their spectral bands under different atmospheric conditions. The new method proved to be successful in not only transferring calibrations but also in detecting and correcting potential instrumental issues, such as tracking problems or temperature dependence of the Silicon detectors in certain spectral bands.

Overall, this method offers a valuable tool for transferring calibration and addressing instrumental issues in photometers with different spectral bands, enabling accurate measurements under diverse atmospheric conditions.