“The Ozone Hole – New studies at Davis, Antarctica”
Space
and Atmospheric Sciences
Wednesday,
21 April 2004, 8:00 P.M.
Physics
Lecture Theatre 1
University
of Tasmania, Sandy Bay
Abstract:
Since
the mid-1980’s, dramatic reductions in stratospheric ozone have been observed over
Antarctica each spring. The cause of these so-called ‘ozone hole’ events has
been conclusively linked with special physical conditions in the Antarctic
atmosphere that convert certain normally inert man-made gases, particularly
chlorofluorcarbons and halons, into forms which can rapidly destroy ozone
molecules. Related processes have also created a long-term decline in ozone
levels outside the tropics, as well as ‘mini’ ozone holes in the Arctic.
In
1987, the Montreal Protocol was enacted to phase out the production of ozone
depleting chemicals. However, due to the relatively long lifetimes of the gases
involved and the time required for industry to adapt, the first signs of an
improvement in atmospheric chemistry are only just starting to emerge. There is
cautious optimism that ozone levels will recover to pre-1980 levels by about
the middle of the current century. However, the problem is far from solved, and
there is still significant work to be done in understanding the long-term
impacts of ozone depletion on living systems and global climate, and in
refining predictions of future ozone trends.
At the Australia’s Davis station in Antarctica, the Australian Antarctic
Division and the Bureau of Meteorology are investigating the microphysics of
ozone depletion. This work involves probing the winter atmosphere with a
sophisticated laser remote sensing instrument called LIDAR to measure the
location and physical properties of thin clouds containing microscopic water
and acid particles. The formation of these clouds chemically alters the
atmosphere, and sets up conditions favourable for ozone destruction. By
combining data from the LIDAR with special in-situ measurements involving
balloons, we are looking closely at the interaction between atmospheric motions
and their impact on cloud structures and ozone levels, which has important
implications for predicting ozone concentrations.
In
this talk, an overview of the ozone depletion problem and behaviour of the
Antarctic ozone hole will be given. This will be followed by a discussion of
the ozone research at Davis, including presentation of initial results.
Andrew
Klekociuk is a research scientist with the Australian Antarctic Division (AAD)
where he heads a small group that operates the Davis atmospheric lidar
experiment. Andrew joined the AAD in 1987 as an expeditioner physicist and
spent 17 months at Macquarie Island investigating the Aurora Australis. This
work lead to a summer sojourn at Mawson in 1990, and auroral observing
campaigns at Macquarie Island and Kotzebue, Alaska in 1991. Since 1995, Andrew
has been intimately involved with the development of the Davis lidar, and spent
the 2000/01 and 2001/02 summers in Antarctica installing and operating the
experiment. Andrew gained a PhD from the University of Tasmania in 1990 through
research in radioastronomy.