Aerosol impacts on forecasts at various temporal scales: the ECMWF perspective. 

In recent years ECMWF has developed the capability to run prognostic aerosols within the Integrated Forecast System (IFS_COMPO). This system is used operationally in the production of the aerosol analysis and 5-day forecasts provided by the Copernicus Atmosphere Monitoring Service. While it is recognized that aerosols are important also for Numerical Weather Prediction at the medium-range, the IFS configuration with prognostic aerosol is too expensive and a climatology derived from IFS_COMPO is instead used in the IFS NWP analysis and 10-day forecast. Recent work has focused on using  emissions from 1993 until present to provide a time-varying climatology to be used also in the reforecasts which provide the calibration of the ECMWF’s seasonal forecast. This new time-varying climatology will also be used in ERA6. 

In this talk we will cover several aspects of aerosol impacts on the ECMWF’s forecasts from the short-to-medium range and from to the seasonal-to-seasonal range. An overview of the CAMS activities related to aerosol model development and data assimilation will also be provided.