The instrument spectral response function (ISRF) of a pixel describes its signal as a function of wavelength of the incoming light. The measurements to derive a monitoring ISRF are performed by spectrally scanning one of the five on-board diode lasers [vanHees2018]. Measurements are taken monthly.

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.

Other websites on TROPOMI
and Sentinel-5 Precursor:

Netherlands Space Office
Airbus Defence and Space