Since 2005 we perform spectral measurement with a mini-MAXDOAS instrument at several measurement campaigns (DANDELIONS I and II, PEGASOS, SEES, CINDI and CINDI-2) and since 2011, continuous measurements of tropospheric columns of NO2 are performed at De Bilt and Cabauw. In 2016 a Pandora was installed in Cabauw, which is part of the Pandonia network.
From the data of these instruments tropospheric columns and low-resolution profiles of NO2 are retrieved, with an in-house developed retrieval method. We are joining the international efforts of harmonisation and determination of best-practice standards via several projects (GEOMON, QA4ECV, FRM4DOAS) and intercomparison campaigns (CINDI and CINDI-2).
The data is used in the validation of satellites and models, e.g. in the semi-operational quarterly validation of Copernicus Atmosphere Monitoring Service (CAMS) Regional Models.