Monitoring the Arctic ozone hole from aircraft

Max Planck Institute for Chemistry: An international team of researchers is investigating ozone depletion in the polar stratosphere using data gathered during flights over the Arctic region at elevations of up to 20 kilometers. The team of atmosphere researchers - among them Stephan Borrmann, Professor at the Institute of Atmospheric Physics of Johannes Gutenberg University Mainz and one of the directors of the Max Planck Institute of Chemistry in Mainz - hopes to discover how long the processes that result in the formation of the hibernal holes in the ozone layer at the polar caps actually take.

It is also expected that the data collected during the flights undertaken with the high-altitude aircraft "M55 Geophysica" will provide insight into what effect climate change is having on the physical and chemical processes that influence the ozone layer. This would make it possible to extrapolate the future development of the ozone layer under the conditions obtained during on-going changes.

The chlorofluorocarbons (CFCs) released by humans on the surface of the earth are gradually transported into the stratosphere. Here the CFCs are exposed to powerful ultraviolet radiation which decomposes the chlorofluorocarbons to finally release chlorine. This chlorine usually reacts with other chemicals and is bound in substances such as hydrogen chloride vapor and chlorine nitrate, which are not detrimental to ozone. However, in the stratospheric clouds located over the poles, the clorine from CFCs can form aggressive ozone-destroying chlorine monoxide radicals (CIO).

Analysis of these clouds is thus essential to the research being conducted by the Mainz team under Stephan Borrmann. And it is these extraordinary but natural clouds that are formed only in the stratosphere over the Arctic and Antarctic regions during the cold of the polar winters that are implicated in the formation of the holes in the ozone layer.

"As the warming of the atmosphere attributable to climate change also has a direct effect on the physical and chemical processes associated with the ozone layer, we urgently need to conduct new research into this aspect," explains Professor Borrmann….

The M55 Geophysica taking off, photo by Stephan Borrmann, from the Max-Planck University website