- INERIS France
- Finnish Meteorological Institute Finland
- University of Toulouse France
- Laboratoire Interuniversitaire des Systèmes Atmosphériques France
- Netherlands Organisation for Applied Scientific Research Netherlands
- French National Centre for Scientific Research France
- French National Institute for Industrial Environment and Risks France
- Norwegian Meteorological Institute Norway
- COMMUNAUTE D'UNIVERSITE ET D'ETABLISSEMENTS UNIVERSITE FEDERALE DE TOULOUSE MIDI-PYRENEES France
- Maastricht University Netherlands
- UNIVERSITE FEDERALE DE TOULOUSE MIDI-PYRENEES France
- Royal Belgian Institute for Space Aeronomy Belgium
- METEO-FRANCE France
- ILMATIETEEN LAITOS Finland
- Royal Netherlands Meteorological Institute Netherlands
- University of Bremen Germany
- INSTITUT NATIONAL DE L ENVIRONNEMENT ET DES RISQUES INERIS France
- METEOROLOGISK INSTITUTT Norway
- University of Bremen, Institute of Environmental Physics Germany
- INSTITUT NATIONAL DE L ENVIRONNEMENT INDUSTRIEL ET DES RISQUES - INERIS France
- Centre National de Recherches Météorologiques France
- Centre National de Recherche Meteorologique France
Multi-axis differential optical absorption spectroscopy (MAX-DOAS) tropospheric NO2 column retrievals from four European measurement stations are compared to simulations from five regional air quality models which contribute to the European regional ensemble forecasts and reanalyses of the operational Copernicus Atmosphere Monitoring Service (CAMS). Compared to other observational data usually applied for regional model evaluation, MAX-DOAS data are closer to the regional model data in terms of horizontal and vertical resolution, and multiple measurements are available during daylight, so that, for example, diurnal cycles of trace gases can be investigated. In general, there is good agreement between simulated and retrieved NO2 column values for individual MAX-DOAS measurements with correlations between 35 % and 70 % for individual models and 45 % to 75 % for the ensemble median for tropospheric NO2 vertical column densities (VCDs), indicating that emissions, transport and tropospheric chemistry of NOx are on average well simulated. However, large differences are found for individual pollution plumes observed by MAX-DOAS. Most of the models overestimate seasonal cycles for the majority of MAX-DOAS sites investigated. At the urban stations, weekly cycles are reproduced well, but the decrease towards the weekend is underestimated and diurnal cycles are overall not well represented. In particular, simulated morning rush hour peaks are not confirmed by MAX-DOAS retrievals, and models fail to reproduce observed changes in diurnal cycles for weekdays versus weekends. The results of this study show that future model development needs to concentrate on improving representation of diurnal cycles and associated temporal scalings.