Copernicus Atmosphere Monitoring Service – Regional Air Quality Production System v1.0

Abstract. The Copernicus Atmosphere Monitoring Service (CAMS) delivers a wide range of free and open products in relation to atmospheric composition at global and re gional scales. The CAMS Regional Service produces daily forecasts, analyses, and reanalyses of air quality in Eu rope. This service relies on a distributed modelling pro duction by 11 teams in 10 European countries: CHIMERE (France), DEHM (Denmark), EMEP (Norway), EURAD IM (Germany), GEM-AQ (Poland), LOTOS-EUROS (the Netherlands), MATCH (Sweden), MINNI (Italy), MOCAGE (France), MONARCH (Spain), and SILAM (Finland). The project management and coordination of the service is con ducted by a Centralised Regional Production Unit. Ev ery day, each model produces 24 h analyses for the previ ous day and 97 h forecasts for 19 chemical species over a spatial domain at 0.1 × 0.1° resolution (approximately 10 km × 10 km), with 420 points in latitude and 700 in longi tude and 10 vertical levels. Six pollen species are also deliv ered for the surface forecasts. The 11 individual models are then combined into an ENSEMBLE median. In total, more than 82 billion data points are made available for public use on a daily basis. The design of the system follows clear technical require ments in terms of consistency in the model setup and forcing fields (meteorology, surface anthropogenic emission fluxes, and chemical boundary conditions). But it also benefits from a diversity in the description of atmospheric processes through the design of the 11 European chemistry-transport models (CTMs) involved. The present article aims to provide a comprehensive tech nical documentation, both for the setup and for the diver sity of CTMs involved in the service. We also include an overview of the main output products, their public dissem ination, and the related evaluation and quality control strat eg