Das Projekt "Testing atmospheric chemistry in anticyclones" wird vom Umweltbundesamt gefördert und von Forschungszentrum Jülich GmbH, Institut für Chemie und Dynamik der Geosphäre ICG-2: Troposphäre durchgeführt. Objective: To understand the processes which control tropospheric ozone and oxidation capacity on a regional and global basis. General Information: There are still severe limits to our understanding of the processes which control tropospheric ozone and oxidation capacity on a regional and global basis. These limits restrict our ability to address many scientific and policy issues, and the aim of this proposal is to employ a well integrated combination of airborne and ground-based measurements and statistical and deterministic models to resolve some of these. Amongst these questions are those relating to Global Change, such as: Is the ozone concentration over the North Atlantic significantly enhanced by human-made emissions? Can the ozone balance be predicted? A second set of questions relate to oxidation processes: How many ozone molecules are formed for each NOX molecule converted into products, including organic nitrates? How does this number depend on the concentration of precursors? Can indirect estimates be made of the main oxidant molecule, hydroxyl? A third set relates more closely to policy issues: What are the relative roles of VOC and NOX in forming ozone over the N Atlantic? Are measured concentrations of NOy and hydrocarbons consistent with European emission inventories? The technique used will be to characterise changes in the chemical composition of summertime European continental air masses as they move over the ocean, and compare them with our current understanding of chemical processes. The air mass from Northern Europe will be followed as they move over the sea in the lower troposphere on the outer edge of an anticyclone, avoiding areas of cloud and precipitation. Concentrations of ozone, NO, NO2, NOy, PAN, individual organic compounds (including organic nitrates), CO, peroxides and depending on the instrument development, peroxy radicals will be measured by the Meteorological Research Flight C-130 aircraft during several horizontal and vertical interceptions of approximately the same air mass during the first two days after it has left the continent. Campaigns will be undertaken in the summers of 1996 and 1997. Supporting measurements will be made at coastal ground sites, and all data will be archived at NILU. Aircraft and ground-based data will be analysed and interpreted using 3-d coupled numerical weather prediction, chemistry-transport and Lagrangian models. A novel and rigorous statistical scheme will be applied to the analysis of the measurements and in the validation of deterministic models of photo-oxidant formation. The programme is divided into five closely related work packages, each with a co-ordinator and with well-defined links to all other parts of the project and the project co-ordinator (University of Bergen): Aircraft campaigns (co-ordinated by MRF); ... Prime Contractor: Universiteet i Bergen, Geophysical Institute, Faculty of Mathematics and Exact Sciences; Bergen; Norway.