The CAMS regional forecasting service provides daily 4-day forecasts of the main air quality species and analyses of the day before, from 7 state-of-the-art atmospheric chemistry models and from the ENSEMBLE median calculated from the 7 model forecasts. The regional service also provides a posteriori reanalyses, using the latest validated observation datasets available for assimilation.

This page describes the 7 operational forecasting and assimilation systems that contribute to the ENSEMBLE, and also the method used for the ENSEMBLE production. For each system, the main components of the model are specified: chemistry schemes, aerosol representation, emissions and deposition, resolved and sub-grid transport, boundary conditions, assimilation system.