Research project CG/DD1/02 (Research action CG)
Context
A study of the chemical composition of the troposphere at the global scale, and in particular of the impact of industrialisation and the biosphere (hydrocarbons emissions) on the abundance of tropospheric ozone and the oxidising capacity of the atmosphere.
Objectives
- Reduce the uncertainties on the chemical and physical processes controlling the global distribution of chemical species in the troposphere, in particular oxidants and chemically-controlled greenhouse gases (methane, ozone);
- Quantify the global budget of tropospheric ozone and its precursors (carbon monoxide, nitrogen oxides, hydrocarbons), as well as the processes determining the abundance of the hydroxyl radical (OH), the « cleansing agent » of the atmosphere;
- Determine the influence of human activities on the chemical composition and the oxidising capacity of the atmosphere, and provide estimates of the possible future evolution of the tropospheric composition;
- Determine the global impact of organic compounds (in particular, biogenic species) on the oxidising capacity of the atmosphere and tropospheric ozone;
- Elucidate the oxidation mechanism of important terpenes in their reaction with hydroxyl radicals using the fast-flow reactor technique;
- Quantitative determination of the product yields of these reactions as a function of various reaction conditions;
- Generate the mechanistic data needed for atmospheric chemistry models in order to estimate the effect of terpenes on the composition of trace gases in the atmosphere such as carbon monoxide, acetone, formaldehyde, acetaldehyde and ozone;
Methodologies
- Development of numerical three-dimensional models for the composition of the global troposphere : IMAGES, already shown to be a useful tool for the investigation of tropospheric processes and for evaluating the impact of human activities, and MOZART, a new model developed mainly at NCAR (National Center for Atmospheric Research, U.S.A.);
- Model validation by comparisons with the available observations of trace gases;
- Studies of tropospheric composition changes since pre-industrial times, and estimation of the possible future evolution, in particular in the framework of our contribution to the IPCC assessment;
- Determination of the global emissions of biogenic organic compounds;
- Studies of the role of biogenic organic compounds on the composition of the troposphere, by means of sensivity studies;
- Use of the fast-flow reactor technique for the simulation of atmospheric chemistry processes at a laboratory scale;
- Development and application of new analytical techniques for qualitative and quantitative determination of the terpenes oxidation products;
- Adaptation and use of existing atmospheric chemistry models RACM (Regional Atmospheric Chemistry Model) and MCM (Master Chemical Model) for simulation of fast-flow reactor experiments.
Partners
The network consists in only two partners:
IASB-BIRA (Belgian Institute for Space Aeronomy, P.I.: Dr. J.-F. Müller), in charge of the modelling aspects of the project, and the Analytical Chemistry Division of the Katholieke Universiteit Leuven (P.I. : Pr. C. Vinckier), in charge of laboratory studies of the OH-initiated oxidation of several important biogenic hydrocarbons.
Deliverables and expected results
- Improved versions of two three-dimensional models of the troposphere;
- Standard techniques and methods for investigation of the oxidation paths of organics with hydroxyl radicals on a laboratory scale;
- New kinetic mechanisms representing the oxidation of several important biogenic organics (monoterpenes);
Scientific collaboration
- National Center for Atmospheric Research, Boulder, Colo., U.S.A.
- Service d’Aéronomie, Université Paris VI, France
- LISA, Université Paris XII, France
- Intergovernmental Panel for Climate Change (IPCC)
- Incorporation in the Eurotrac project CMD (Chemical Mechanism Development)
Anthropogenic and biogenic influences on the oxidizing capacity of the atmosphere: final report
Müller, J-F - Vinckier, C. - Wallens, S. ... et al. Brussels: OSTC, 2001 (SP0918)
[To download]
[Exhausted]
Anthropogenic and biogenic influences on the oxidising capacity of the atmosphere: summary
Brussels: OSTC, 2001 (SP0994)
[To download]
Influences anthropiques et biogéniques sur la capacité oxydante de l'atmosphère: synthèse
Bruxelles: SSTC, 2001 (SP0995)
[To download]
Antropogene en biogene invloeden op de oxiderende capaciteit van de atmosfeer: synthese
Brussel: DWTC, 2001 (SP0996)
[To download]
