The objectives of the G-IDAS sub-project are:

• Improvement of global data assimilation for greenhouse and reactive gases and aerosols, including use of new streams of observations, in close collaboration with the G-GHG, G-RG and G-AER subprojects and within the framework of the integrated global system for assimilation of data on atmospheric composition developed by the GEMS project;
• Assessment of the interaction between the greenhouse-gas, reactive-gas and aerosol components of the integrated system, and periodic creation and pre-production testing of upgraded versions of the system;
• Routine near-real-time and delayed-mode production of analyses and forecasts of atmospheric composition;
• Production of a new reanalysis of atmospheric composition from 2003 onwards, and of reanalyses for shorter periods of special interest using alternative versions of the assimilation system;
• Development and routine creation of products derived from the results of G-IDAS production, supplemented by results from ECMWF climate reanalysis and meteorological operations;
• Monitoring and routine validation of the G-IDAS production streams;
• Development and maintenance of the MACC central website and its systems for provision of service and project information, display of results and supply of data products