To monitor changes in air quality and climate, several types of observation have to be combined: continuous observation by satellites from space; observation by ground-based observatory networks; and observation by instruments on planes operated by airlines. But the disparity of these observations and the sheer number and variety of databases containing the results have hampered the exploitation of this immense body of information.

The European GEOMON** project scientific kick-off meeting took place in Paris on February 12 and 13. GEOMON aims to construct an integrated pan-European atmospheric monitoring program from existing observation systems. It forms part of an international strategy ratified by a large number of countries to establish an integrated and coordinated system*** of global observation of the Earth (the Global Earth Observation System of Systems - GEOSS).

Over the next four years, the 38 research laboratories within GEOMON will work together to set up this important tool. In France, the project involves teams from CEA, which is coordinating the project, and from CNRS/INSU, CNES and Université de Versailles Saint-Quentin-en-Yvelines****.

The multitude of existing measurement networks will be harmonized to produce compatible data, and methods will be developed to combine data recorded on the ground and by satellites. Finally, a common database will be set up. This will give all the European partners access to coherent observations of atmospheric composition.

The system will make it possible to monitor changes in the concentration of greenhouse gases, the chemical composition of the troposphere (0-12 km) and stratosphere (12-50 km) and the distribution of all types of particle (carbon, volcanic, anthropogenic, soot, desert dust, etc.), particularly above Europe. It will thus help to:
- improve the prediction of future changes in climate and air quality;
- evaluate the effects on atmospheric composition and climate of major international regulations to reduce anthropogenic emissions (Kyoto, Montreal, etc.).

*The National Institute of Sciences of the Universe
**GEOMON is a scientific project within the 6th EU Framework Programme for Research and Development
***The instruments and networks will be integrated into a larger system, which includes space missions and the development of digital tools to ensure all the measurements are compatible.
****French laboratories involved in GEOMON: Laboratory of Climate and Environmental Sciences (IPSL/LSCE, a joint CEA, CNRS and Université Versailles Saint-Quentin laboratory), Aeronomics Service (IPSL/SA, a joint CNRS, Université Pierre et Marie Curie and Université Versailles Saint-Quentin laboratory), Laboratory of Dynamic Meteorology (IPSL/LMD, a joint CNRS, École polytechnique, Université Paris VI and ENS Paris laboratory), Inter-University Laboratory of Atmospheric Systems (LISA, a joint CNRS, Université Paris VII and Université Paris XII laboratory), the Laboratory of Atmospheric Optics (LOA, a joint Université Lille 1 and CNRS laboratory) and the Laboratory of the Atmosphere and Cyclones (LACy, a joint CNRS, Université La Réunion and Météo-France CNRM laboratory)