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Polar Stratospheric Ozone Changes, SPARC, and the International Polar Year

As a part of the grand experiment of the International Geophysical Year (IGY) in 1957, ozone was measured in Antarctica using Dobson spectrometers.  The aim was to measure the abundances and variations of ozone, which was thought to be a passive stratospheric tracer in this region, to understand the dynamics of the Antarctic stratosphere.  What emerged in 1985 with the publication of Farman et al. (Nature, 315, p 207, 1985) was the clearest picture of an enormous annual depletion of ozone in the austral spring over Antarctica – the infamous Antarctic Ozone Hole.  In less than 5 years, it was proven that the ozone hole was caused by human emitted fluorochlorocarbons (CFCs) and since then the ozone hole has been a "poster child" for showing how humans can cause global scale changes.  The discovery of the ozone hole, its association with the CFCs, and its continued larger and larger depletions were the key factors that led to the Montreal Protocol and its amendments to ban CFCs, and the first truly international treaty to preserve the environment.  Thus the Antarctic Ozone Hole became inarguably one of the most recognized environmental issues of the 20th century, recognized by people everywhere in the world.  The Arctic ozone changes, though lesser in magnitude than the Antarctic ozone hole, are by no means of lesser importance.

The science of the polar ozone losses – the atmospheric dynamics, chemistry, and radiation understanding – was and, continues to be a major theme of Stratospheric Processes and their Role in Climate (SPARC), a WCRP project.  The SPARC community was instrumental in understanding the polar ozone depletions, and the many advances that have been made regarding the stratosphere to date.  We in the SPARC community are confident that this progress will con-tinue.

In light of such an internationally visible, scientifically important, and societally relevant event of the 20th century in the polar region, it would be inappropriate not to include stratospheric ozone issues as an important theme in the International Polar Year (IPY).  Not only will it clearly provide a context for IPY but also show how international activities such as IGY and IPY provide scientifically and societally important information.  It also provides a wonderful opportunity to describe the brief, but eventful, history of the stratosphere and benefits, foreseen and unforeseen, of activities such as the IPY.  We strongly urge the National and International communities involved in IPY to include the polar stratosphere in the schedule.

SPARC co-Chairs

Alan O’Neill(1),   A.R. Ravishankara(2)

(1) Data Assimilation Research Centre, Reading, UK (alan@met.reading.ac.uk)

(2) NOAA-Aeronomy Laboratory, Boulder, USA (A.R.Ravishankara@noaa.gov)