Objetivo a) to measure regularly and simultaneously the vertical distribution of several source gases (CFCs, H2O, N2O) together with ozone, NO2, OClO, BrO, background and volcanic aerosols, temperature and pressure, at three latitudes in the lower stratosphere, from the tropopause up to 30 km, using relatively cheap and small balloon borne instruments; b) to combine the results of the above measurements with those of instruments in orbit for the upper levels for retrieving the complete stratospheric profiles of the species; c) to simulate the results with 3D CTM and Lagrangian photochemical models to differentiate the transport and chemical terms.The approach is to fly a combination of light instruments below relatively small volume (5.000 or 10.000 m3) and easy to operate balloons which can be launched on short notice as successfully demonstrated during EASOE and SESAME. The flight train will associate the following instruments: -the SAOZ payload from CNRS: uv-visible spectrometer, 22 kg including a Global positioning System, an ARGOS beacon, temperature and pressure sensors, for remote measurements by solar occultation of ozone. NO2, OClO and BrO by uv-visible spectrometry and tentatively, H2O and CH4 with a IR spectrometer at 1.6 5m; -the instrument DESCARTES of the University of Cambridge (20 kg, no telemetry) for in-situ sampling of CFC-11 and CFC-12, CFC-113, N2O and possibly CH4, analysed by gas chromatography after the recovery of the payload; -the Laser Backscatter sonde LABS of the Italian CNR-IFA (6kg), for in-situ measurements of the aerosol backscattering ratio and polarisation (liquid vs solid particles). They will be launched at three or four sites: -at the Norwegian Andoya Rocket Range (69 N); -at the French CNES balloon centres of Aire sur l'Adour (fall to spring) and Gap (summer); -at Nairobi at the Equator by a French CNES team in cooperation with local authorities. Each year, three balloons will be launched in winter and spring in the Arctic in PSCs conditions (two inside the vortex, one outside) and two at mid-latitude (early and late winter) for investigating the transport across the vortex edge, PSCs, possible denitrification and dehydration and resulting heterogeneous chlorine and bromine activation. One balloon will be flown at each latitude in summer for looking at the vertical distribution under low meridional transport conditions. Three balloon flights will take place at the equator/tropics in early spring when the upwards branch of the Hadley cell is the most active. The intention is to supplement the balloon flights with ground-based measurements at or near the three sites. The instruments available are the following: -Scandinavia: temperature, ozone and aerosol lidar ALOMAR at Andoya, SAOZ spectrometer, ozone and backscatter sondes at Sodankyla in Finland; -France: NDSC primary station of OHP: temperature, ozone and aerosol lidar, SAOZ spectrometer, ozone sondes; -Equator/tropics: SAOZ spectrometer at Nairobi, Kenya or/and Bauru, Brasil The data resulting from the flights will be combined altogether. The relationship between the vertical distribution of the tracers and ozone will be investigated by 3-D chemical-transport modelling and the fast gas and heterogeneous chemistry (diurnal variation, activation) by a Lagrangian approach. Ámbito científico engineering and technologyelectrical engineering, electronic engineering, information engineeringelectronic engineeringsensorsnatural sciencesearth and related environmental sciencesatmospheric sciencesmeteorologyatmospheric circulationnatural scienceschemical sciencesinorganic chemistryhalogensnatural sciencesphysical sciencesopticslaser physics Programa(s) FP4-ENV 2C - Specific programme of research and technological development in the field of environment and climate, 1994-1998 Tema(s) 01020101 - Stratospheric chemistry and depletion of the ozone layer Convocatoria de propuestas Data not available Régimen de financiación CSC - Cost-sharing contracts Coordinador CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE Aportación de la UE Sin datos Dirección Route des Gètines 92371 VERRIERES-LE-BUISSON Francia Ver en el mapa Coste total Sin datos Participantes (2) Ordenar alfabéticamente Ordenar por aportación de la UE Ampliar todo Contraer todo NATIONAL RESEARCH COUNCIL OF ITALY Italia Aportación de la UE Sin datos Dirección Via Fosso del Cavaliere 100 00133 ROMA Ver en el mapa Coste total Sin datos University of Cambridge Reino Unido Aportación de la UE Sin datos Dirección Lensfield Road CB2 1EW Cambridge Ver en el mapa Coste total Sin datos