Atmospheric composition forecast and assessments

Atmospheric aerosols (tropospheric and stratospheric) are of great importance because of their impacts on human health, visibility, the Earth's climate, the stratospheric ozone layer, and continental and maritime ecosystems, requiring dedicated monitoring of their concentrations and properties at European and global scales. Aerosol models range from very basic to very complicated schemes and the correct balance between needed sophistication and available computing resources needs to be found. CAMS currently uses a simple bin scheme for its near-real-time forecasts and the reanalysis (IFS-LMD), while implementing a more elaborate modal scheme for the future (IFS-GLOMAP).

The IFS-LMD aerosol scheme is the scheme that was introduced to add aerosol modelling to the ECMWF IFS forecasting system. It is currently used for the daily analysis and 5-day forecast and was also used for the MACC reanalysis.
 

The operational CAMS global assimilation and forecasting system uses fully integrated chemistry in the ECMWF Integrated Forecasting System (IFS). The version of the IFS is named Composition-IFS (C-IFS). C-IFS makes it possible (i) to use the detailed meteorological simulation of the IFS for the simulation of the fate of constituents, (ii) to simulate atmospheric chemistry globally at high resolution because of the computational parallel efficiency of the IFS, (iii) to use the IFS data assimilation system to assimilate observation of atmospheric composition and (iv) to simulate feedback between atmospheric composition and weather. Different chemical schemes can be used with the current operational version being based on the CB05 scheme.

In the current configuration, chemistry originating from the TM5 CTM, has been fully integrated into the IFS forecasting model. This version applies 54 tracers and 120 reactions and focuses on tropospheric ozone-CO-NMVOC chemistry. Stratospheric ozone is modelled with a linearized scheme. A more extensive description can be found in this document.