Irradiance measurements via diffusers QVD1 and QVD2, and calibration measurements with the white-light source (WLS) and the LED in the SWIR module (DLED) are used to monitor the stability of the entire instrument and the on-board light sources. All measurements are normalized by taking the ratio with reference measurements from the end of the commissioning phase, when the instrument was stable.
- swir: Ratios of normalized signals as DLED / QVD1, DLED / QVD2, DLED / WLS, WLS / QVD1, WLS / QVD2, QVD1 / QVD2, and background measurements of DLED, QVD1, QVD2, WLS.
- trend: Median of the normalized detector signals of DLED, QVD1, QVD2, WLS as a function of time.
TROPOMI is a collaboration between Airbus Defence and Space Netherlands, KNMI, SRON and TNO, on behalf of NSO and ESA. Airbus Defence and Space Netherlands is the main contractor for the design, building and testing of the instrument. KNMI and SRON are the principal investigator institutes for the instrument. TROPOMI is funded by the following ministries of the Dutch government: the Ministry of Economic Affairs, the Ministry of Education, Culture and Science, and the Ministry of Infrastructure and the Environment.