Using Aerosol and Ozone Forecasting to Improve Numerical Weather Prediction at ECMWF

The European Centre for Medium-Range Weather Forecasts (ECMWF) is a leading center for global numerical weather prediction (NWP). In the last decade, ECWMF has build the capacity for operational atmospheric composition (AC) forecast and assimilation as part of it Integrated Forecasting System. Global atmospheric composition forecast and re-analysis are now carried out operationally at ECMWF by the Copernicus Atmosphere Monitoring Service (CAMS) funded by the European Union.

The integrated CAMS AC-NWP forecasting system at ECMWF has been used operationally to take into account the effects of AC-NWP feedbacks such as the direct radiative effect. While the importance of composition is well established in climate modelling, the impact of these these feedbacks is more difficult to demonstrate for shorter time scales using classic NWP scores. However, recent improvements in modelling and data assimilation of AC as well as a more targeted NWP evaluation strategy has clearly shown the benefits of an integrated AC-NWP system at ECMWF.

We present recent results from the CAMS system to include prognostic representations and improved climatologies of aerosols and ozone in the radiation scheme. We will discuss the impact biases and spatial variability of ozone and aerosol as well aerosol speciation on the mean NWP results as well as for specific events. We will present our strategy to first improve climatologies in a consistent way before prognostic AC representations are applied.