Monitoring atmospheric composition using satellite-ground-based synergies P. Ciais (1), C. Textor (1), M. Logan (1), P. Keckhut (2), B. Buchmann (4), S. Godin-Beekmann (2), G. de Leeuw (5), M. De Maziere (6), E. G. Nisbet (3), P. Rayner (1), M. Schulz (1), K. Torseth (7) (1) LSCE/IPSL (CEA-CNRS-UVSQ), France, (2) Service d’Aeronomie/IPSL, France, (3) Royal Holloway, University of London, UK, (4) EMPA, Switzerland, (5) University of Helsinki, Dept. of Physical Sciences, Helsinki, Finland & Finnish Meteorological Institute, Helsinki, Finland, (6) Belgian Institute for Space Aeronomy, BIRA-IASB, Belgium, (7) Norwegian Institute for Air research NILU, Norway GEOmon This poster gives an overview of the latest results from the first year of the European 6th Framework project GEOmon (Global Earth Observation and Monitoring The overall goal of the GEOmon project is to sustain and analyze European ground-based observations of atmospheric composition (complementary with satellite measurements) in order to quantify and understand ongoing changes. The project is a first step towards building an integrated pan-European Atmospheric Observing System for long-lived greenhouse gases, reactive gases, aerosols, and stratospheric ozone. GEOmon is a precursor of the GMES Atmospheric Service Insitu component and a European contribution to GEOSS. Scientific Questions  What are the regional European trends and variability of atmospheric composition in relation to changes in surface emissions?  How to validate and integrate satellite observations with ground-based and airborne observations to obtain a coherent picture?  What are the global trends of atmospheric composition, and how to reduce the uncertainties of surface emissions and atmospheric processes? Activity 1: Greenhouse gases and Global Warming Activity 2: Reactive Gases, Pollutants and Climate Activity 2: Atmospheric Aerosols and Climate Activity 5: Integration and Supporting Modelling Studies Activity 4: Stratospheric Ozone and Climate Activity 6: System Architecture and Outreach Strategy  Deploy new ground-based remote sensing stations for satellite ground- truthing  Integrate ground-based, aircraft and satellite observations using advanced numerical transport-chemistry models  Build upon existing networks and improve their harmonization  Establish the prototype of a pan-European atmospheric observing system of greenhouse gases, reactive gases, aerosols, and stratospheric ozone  Create a ‘One stop shop’ data centre for European atmospheric data  Provide data storage and ongoing accessibility to data (past and present projects) The GEOmon project  Integrated Project of the 6 th European Commission Framework Programme  38 participating institutions, 4 years’ duration (started in February 2007)  Coordination: P. Ciais, C. Textor, M. Logan (CEA-LSCE), P.Keckhut (CNRS-SA), France  Contact: GEOmon data centre Surface observatories WP1.1: In situ (17 sites) monitoring of CO 2 and CH 4 in the European boundary layer. Near real-time data now from several sites (e.g. Paris, London) WP 1.2 CARIBIC Flying laboratory Measurement of ~100 species (trace gases, aerosol parameters) at 9-12 km altitude (UTLS), plus 2-4 profiles per flight (thus linking ground-based with satellite observations) Measuring the modification of solar radiation by the atmosphere from the ground or with the earth surface (satellites) WP 1.3 Measuring the modification of solar radiation by the atmosphere from the ground or with satellites: FTIR techniques. Flask sampling sites Tall towers Rapid delivery products can be obtained at and at the GEOmon data centre.