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Ozone : climate-chemistry interactions

Objective

To increase our understanding of ozone's role as a greenhouse
gas.


The project will focus on identifying and understanding the
changes in the ozone content of the upper troposphere and the
lower stratosphere, and both the causes and the effects of these
changes will be studied with a wide range of atmospheric models.
Emphasis will be put on identifying possible regional differences
in the trends and in the climate response to the changed
radiative forcing, rather than on globally averaged quantities.

The workplan is divided into four subtasks: data analysis,
chemical modelling, radiative transfer modelling, and
climate modelling.

In the data analysis part both ozone sonde observations and
satellite measurements of total ozone will be analyzed in order
to get a coherent picture of the current and past trends in the
ozone distribution. Specifically we will try to determine how
widespread the ozone loss that is observed in the lower
stratosphere is, as well as where exactly the crossover between
this stratospheric ozone loss and the corresponding tropospheric
increase occurs.

Two- and three-dimensional chemical models will be used as tools
both for understanding what determines the observed trends, and
for predicting future trends in the ozone distribution. A key
issue for the chemical modelling is to determine the extent to
which the lower stratospheric ozone reductions seen over the last
decade can be attributed to increased emissions of CFCs and
halons. In addition the impact on upper troposheric ozone of
NOx emissions from commercial flights will be studied.

The impact of various observed and modeled profiles of ozone on
the atmospheric heating rates will be studied using radiative
transfer models. This work will be particularly useful for
putting the ozone/climate issue into the proper perspective, as
it will quantify how important the latitudinal (or regional)
changes in radiative forcing can be, compared to the radiative
forcing from other greenhouse gases.

Finally the atmospheric response to changes in heating rates
through a redistribution of ozone will be studied using climate
models. This work will help in identifying possible positive or
negative feed-back mechanisms relevant for the ozone/climate
question, and simulations with ozone as a predicted variable in a
general circulation model may also give some ideas about how the
atmsphere would redistribute the ozone in response to externally
enforced ozone reductions.

Funding Scheme

CSC - Cost-sharing contracts

Coordinator

DANISH METEOROLOGICAL INSTITUTE
Address
100,Lyngbyvej 100
2100 Koepenhagen
Denmark

Participants (5)

ARISTOTLE UNIVERSITY OF THESSALONIKI
Greece
Address
Aristotle University Of Thessaloniki
54006 Thessalonki
Institut Pierre Simon Laplace des Sciences de l'Environnement Global
France
Address
4 Place Jussieu
75252 Paris
UNIVERSITY OF READING
United Kingdom
Address
Earley Gate 2, Whiteknights, Palmer Building
RG6 2AU Reading / Silchester
University of Oslo
Norway
Address

0315 Oslo-blindern
Università degli Studi dell'Aquila
Italy
Address
Via Vetoio 10
67010 Coppito L'aquila