Forget blue skies research, it is clouds that have focused minds at the
University of Leicester where scientists are tackling the causes of ozone depletion.
Atmospheric scientists in the Department of Physics and Astronomy are
spearheading the MAPSCORE project, a European Commission Environment project
which investigates a major cause of ozone depletion — high altitude polar
clouds which activate the chlorine originally from CFCs and lead eventually to
severe ozone destruction.
Leicester researchers have discovered it is possible to map the global
distribution of polar clouds from space, and to determine their composition.
For the first time, scientists can see maps of clouds around the globe, via the
internet, as soon as the ESA ENVISAT satellite detects them. This knowledge has
already been put to good use in examining clouds and ozone loss near Europe
during the last winter. Now the Leicester scientists are observing the evolution
of the Antarctic ozone hole which last year behaved in a unprecedented fashion
and showed that there are still surprises in the ozone story.
University of Leicester scientist Dr John Remedios, who is coordinating the
MAPSCORE project, said: "ENVISAT makes it possible for us to map Polar
Stratospheric Clouds in ‘near real-time’ for the first time. We have
unprecedented detail and can even define the types of cloud that are driving
ozone loss. This information guides our atmospheric modelling of how these polar
stratospheric clouds form and their influence. This is important because we need
to be able to predict how much ozone will be depleted in future years and polar
stratospheric clouds are a key part of the problem".
Clouds form in the polar stratosphere at altitudes of 12-28 km during the cold
winter months. Chlorine from CFCs can be released from the surface of the cloud
particles, and incident sunlight in the spring stimulates the rapid destruction
of ozone by the ‘active’ chlorine in the polar stratospheric clouds. However,
the overall occurrence and extent of PSCs in polar winter needs to be
quantified, and it is here that ENVISAT’s daily monitoring of the atmosphere is
vital as part of a wider effort to tackle this problem.
Dr John Remedios said: "For this reason, we are participating very actively in
the latest European Commission campaign, ‘Vintersol’, which rallies over 300
scientists from over 14 European countries to tackle the problem of measuring
and understanding the causes of mid-latitude ozone depletion, and to predict
future ozone levels." In the first Arctic phase, the Vintersol study was
co-ordinated with a large NASA campaign, SOLVE-2, which gives a measure of the
large international scientific effort involved in this work.
Stratospheric ozone levels over Europe have been decreasing at a rate of 6% per
decade each spring, allowing more ultra-violet radiation to reach the ground.
Information gleaned from the MAPSCORE project concerning ozone depletion by PSCs
will enable Vintersol campaign scientists to identify future trends in ozone
levels, and determine whether we can expect an increased health risk for
Europeans of the future.
The MAPSCORE project is funded by the Environment Programme of the European
Commission under Framework V. The Natural Environment Research Council has
recently announced a new grant to support the development of the ENVISAT cloud
mapping and to help Leicester scientists design a new space instrument which
could perform an even better job of monitoring these important clouds.
The ENVISAT satellite is a major ESA mission monitoring the health of the planet.
