Semi-blind intercalibration and intercomparison field campaign of ground-based UV-Visible DOAS instruments with external referee. Complemented by mobile DOAS systems and an exhaustive range of measurements of aerosols, ozone and other UV-Visible trace gases. Primary goals: (i) to intercalibrate instruments and assess mutual consistency of their measurements, (ii) to get NDACC/ACTRIS-CREGARS certification for new instruments, (iii) to assess and improve FRM maturity of the measurements for the validation of the Air Quality and Ozone satellite constellations. Primary target species: atmospheric NO2 and O3; secondary targets: HCHO, CHOCHO and aerosols; others: HONO, BrO and H2O.
The CINDI-3 campaign took place in Cabauw (NL) from 21 May to 24 June 2024. Over 100 researchers from 16 countries participated in the campaign, operating 44 instruments to compare and intercalibrate measurements of air pollutants and ozone and to support the validation of space-based sounders such as Sentinel-5P TROPOMI and Aura OMI. The stationary UV-VIS observations by MAX-DOAS and a few PGN instruments were complemented with ancillary measurements from ozone and aerosol lidars, NO2 and ozone sondes, long-path DOAS and in-situ instruments. Mobile measurements of the distribution of pollutants around Cabauw, De Bilt and Rotterdam were also made during selected days using instruments mounted on cars, bikes and a small research aircraft. The analysis of the campaign data is in progress.