Objectif Problems to be solvedSTACCATO is a comprehensive study of stratosphere-troposphere exchange (STE) processes and their effect on atmospheric chemistry. STE is a key factor controlling the budget of ozone, water vapour and other substances in both the troposphere and lower stratosphere. Earlier studies of STE have concentrated primarily on the flux of air or trace constituents across the tropopause alone. Shallow exchange events are indeed partially reversible in nature and only produce compositional changes in the tropopause region. However, deep STE events are largely irreversible and have a highly significant and lasting impact on atmospheric chemistry through a substantial body of the atmosphere, even down to the earth's surface. Up until now, the importance of STE for the ozone budget relative to photochemical ozone formation from natural and anthropogenic precursor emissions, including those from aircraft, has remained uncertain. A comprehensive description of STE, which STACCATO seeks to provide, is thus a vital component for understanding the chemical composition of the atmosphere and its consequences.Scientific objectives and approachSTACCATO is undertaking a first detailed investigation of STE mixing of stratospheric and tropospheric air. Meteorological processes under investigation include the creation of fine-scale structures by chaotic advection, radiative decay of tracer filaments and mixing through turbulence in the free troposphere. The non-linear effect of this mixing on chemical processes is addressed with a box model as well as with a global model. The impact of STE on the oxidizing capacity of the troposphere, relative to other factors, is examined with two global chemistry models coupled to climate models. The fate of aircraft emissions is being addressed using passive tracer simulations and including these in the chemistry models. A new three-dimensional Lagrangian perspective of STE, focussing on deep exchange events, is being developed. The variability and recent trends of STE is being assessed, based on very high quality meteorological re-analysis data. Potential future changes to STE significance are being computed under scenarios of climate change obtained from simulations with two climate models. A major comparison of seven methods and models used to calculate STE is being carried out to find strengths and weaknesses of each approach and to identify reasons for discrepancies. A measurement dataset is being created to validate model results and to provide an independent estimate of the strength of STE. This includes the first long-term monitoring of two radio nuclides, beryllium-7 and beryllium-10.Expected ImpactsProvision of an observational estimate of the strength of STE based on two years of radio nuclide measurements. Analysis of the strength of STE and its variability during the last 15 years, based on Lagrangian models set up on meteorological re-analyses. Study of the possible changes in STE in a future climate. Assessment of the importance of STE for atmospheric chemistry relative to other factors. Improved knowledge of the role of mixing. Champ scientifique natural scienceschemical scienceselectrochemistryelectrolysisengineering and technologymechanical engineeringvehicle engineeringaerospace engineeringaircraftnatural sciencesearth and related environmental sciencesatmospheric sciencesclimatologyclimatic changesnatural sciencesearth and related environmental sciencesatmospheric sciencesmeteorologytroposphere Programme(s) FP5-EESD - Programme for research, technological development and demonstration on "Energy, environment and sustainable development, 1998-2002" Thème(s) 1.1.4.-2. - Key action Global Change, Climate and Biodiversity Appel à propositions Data not available Régime de financement CSC - Cost-sharing contracts Coordinateur TECHNICAL UNIVERSITY OF MUNICH Contribution de l’UE Aucune donnée Adresse Am hochanger 13 85 354 Freising Allemagne Voir sur la carte Coût total Aucune donnée Participants (10) Trier par ordre alphabétique Trier par contribution de l’UE Tout développer Tout réduire ARISTOTLE UNIVERSITY OF THESSALONIKI Grèce Contribution de l’UE Aucune donnée Adresse Aristotle university of thessaloniki 54006 Thessalonki Voir sur la carte Coût total Aucune donnée MAX-PLANCK-GESELLSCHAFT ZUR FOERDERUNG DER WISSENSCHAFTEN E.V. Allemagne Contribution de l’UE Aucune donnée Adresse Bundesstra¯e 55 20146 Hamburg Voir sur la carte Coût total Aucune donnée NATIONAL TECHNICAL UNIVERSITY OF ATHENS Grèce Contribution de l’UE Aucune donnée Adresse 9,heroon polytechniou 9 15780 Athens Voir sur la carte Coût total Aucune donnée ROYAL NETHERLANDS METEOROLOGICAL INSTITUTE Pays-Bas Contribution de l’UE Aucune donnée Adresse 10,wilhelminalaan 10 3730 AE De bilt Voir sur la carte Coût total Aucune donnée SECRETARY OF STATE FOR DEFENCE - MINISTRY OF DEFENCE Royaume-Uni Contribution de l’UE Aucune donnée Adresse London road, sutton house room sg/12 RG12 2SZ Bracknell Voir sur la carte Coût total Aucune donnée SWISS FEDERAL INSTITUTE OF TECHNOLOGY ZUERICH Suisse Contribution de l’UE Aucune donnée Adresse 101,hoenggerberg 8093 Zurich Voir sur la carte Coût total Aucune donnée UNIVERSITAET FUER BODENKULTUR WIEN Autriche Contribution de l’UE Aucune donnée Adresse 18,turkenschanzstrasse 18 1180 Wien Voir sur la carte Coût total Aucune donnée UNIVERSITY OF BERNE Suisse Contribution de l’UE Aucune donnée Adresse 3,freiestrasse 3 3012 Bern Voir sur la carte Coût total Aucune donnée UNIVERSITY OF VIENNA Autriche Contribution de l’UE Aucune donnée Adresse Währinger strasse 17 1090 Wien Voir sur la carte Coût total Aucune donnée UTRECHT UNIVERSITY Pays-Bas Contribution de l’UE Aucune donnée Adresse 5,princetonplein 5 3584 CC Utrecht Voir sur la carte Coût total Aucune donnée