Photochemical Activity and solar Ultraviolet Radiation

Información del proyecto

PAUR

Identificador del acuerdo de subvención: ENV4950048

Proyecto cerrado

Fecha de inicio 1 Febrero 1996

Fecha de finalización 31 Enero 1998

Financiado con arreglo a

• Specific programme of research and technological development in the field of environment and climate, 1994-1998

Coste total

Sin datos

Aportación de la UE

Sin datos

Coordinado por

Aristotle University of Thessaloniki
Greece

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 (EuroSciVoc)

• ciencias naturales › ciencias químicas › química orgánica › aldehídos
• ciencias naturales › ciencias químicas › electroquímica › electrólisis
• ciencias naturales › ciencias químicas › química orgánica › hidrocarburo
• ciencias naturales › ciencias de la tierra y ciencias ambientales conexas › ciencias de la atmósfera › meteorología › radiación solar
• ciencias naturales › ciencias de la tierra y ciencias ambientales conexas › ciencias de la atmósfera › meteorología › troposfera

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

Datos no disponibles

Régimen de financiación

CSC - Cost-sharing contracts

Coordinador

Aristotle University of Thessaloniki

• Aportación de la UE: Sin datos
• Dirección: 54006 Thessaloniki ; Grecia
• Coste total: Sin datos

Participantes (4)

CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE

Francia

• Aportación de la UE: Sin datos
• Dirección: Route des Gètines ; 92371 VERRIERES-LE-BUISSON
• Coste total: Sin datos

Ludwig-Maximilians-Universität München

Alemania

• Aportación de la UE: Sin datos
• Dirección: Hohenbachernstraße 22 ; 85354 Freising
• Coste total: Sin datos

STOCKHOLM UNIVERSITET

Suecia

• Aportación de la UE: Sin datos
• Dirección: UNIVERSITETSVAEGEN 10 ; 10691 STOCKHOLM
• Coste total: Sin datos

UNIVERSITY OF OSLO

Noruega

• Aportación de la UE: Sin datos
• Dirección: Moltke Moes Vei 31 ; 0315 OSLO
• Coste total: Sin datos