Objetivo The objective of this project is to study the different steps in a sequence going from reduced stratospheric ozone through increased penetration of UV-B solar radiation through the atmosphere and increased photochemical activity in the lower atmosphere to the evaluation of the impact on regulations which aim at reducing ozone levels in polluted regions. It will be modelled and measured how ozone and other photochemically active species are affected by enhanced UV-B radiation in European regions with a strong influx of UV-B radiation during summer time and where significant increases in surface ozone levels have already been observed, for example in the Mediterranean region. For this specific task the Aegean sea and Athens basin have been selected for a campaign in this study. In this area, UV-B fluxes (and photochemical activity) during summertime are among the highest in Europe while different environmental quality conditions can be encountered in different sites. It is thus an area well suited for studies of the links between reductions in ozone column densities and enhanced surface fluxes of UV-B radiation. Similar studies of the UV-B/ozone relations will be performed in southern Germany (close to the Alps) where UV-B fluxes are also enhanced and where similar UV-B increases have been reported.The project involves one experimental part and one modelling part that also includes model validation through comparisons with the set of compounds which will be measured simultaneously during the proposed campaigns. The experimental part of the study includes two campaigns, one in Greece during summer 1996 and a second one in Bavaria during summer 1997. The campaign in Greece is jointly organized with the ATOP project to additionally provide actinic UV-B fluxes up to the tropopause and includes: 1.Continuous measurements of spectral UV-B irradiances with double monochromators (Brewer, double in Greece, Bentham in Bavaria) along with conventional total UV-B dosimeters (broad band). 2. Total columns of O3, SO2, aerosol vertical distribution with LIDAR and vertical ozone distribution with ozonesondes. 3. Photolysis rates of NO2 and O3. 4. Surface ozone, NO, NO2, CH2O, hydrocarbons and PAN. 5. Meteorological observations at ground, in the free troposphere and in the lower stratosphere. 6. Aircraft measurements of spectra of solar actinic fluxes, ozone, water vapour and formaldehyde. The modelling part includes two different types of models: 1. Calculation of solar fluxes and photodissociation rates in polluted regions will be performed with a radiative transfer model which accurately calculates photodissociation rates in the atmosphere at different locations, different solar elevation and different atmospheric conditions in which clouds and particles are included in the calculation scheme. The calculated solar radiation fluxes at UV-A and UV-B wavelengths and photolysis rates for ozone and NO2 will be compared with observations. 2. Calculation of the chemical oxidation which is representative for ozone generation in polluted regions will be done with a regional model with an extended chemical scheme which calculates the diurnal variations of photodissociation rates and the concentration of approximately 50 chemical species involved in the ozone generating process. It calculates the rapid variations of key compounds like OH and HO2 which are important for ozone generation in rural areas. Ámbito científico natural scienceschemical sciencesorganic chemistryaldehydesnatural scienceschemical scienceselectrochemistryelectrolysisnatural scienceschemical sciencesorganic chemistryhydrocarbonsnatural sciencesearth and related environmental sciencesatmospheric sciencesmeteorologysolar radiationnatural sciencesearth and related environmental sciencesatmospheric sciencesmeteorologytroposphere 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 Aristotle University of Thessaloniki Aportación de la UE Sin datos Dirección 54006 Thessaloniki Grecia Ver en el mapa Coste total Sin datos Participantes (4) Ordenar alfabéticamente Ordenar por aportación de la UE Ampliar todo Contraer todo CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE Francia Aportación de la UE Sin datos Dirección Route des Gètines 92371 VERRIERES-LE-BUISSON Ver en el mapa Coste total Sin datos Ludwig-Maximilians-Universität München Alemania Aportación de la UE Sin datos Dirección Hohenbachernstraße 22 85354 Freising Ver en el mapa Coste total Sin datos STOCKHOLM UNIVERSITET Suecia Aportación de la UE Sin datos Dirección UNIVERSITETSVAEGEN 10 10691 STOCKHOLM Ver en el mapa Coste total Sin datos UNIVERSITY OF OSLO Noruega Aportación de la UE Sin datos Dirección Moltke Moes Vei 31 0315 OSLO Ver en el mapa Coste total Sin datos
