Paper in Press
GEOPHYSICAL RESEARCH LETTERS, doi:10.1029/2011GL049784
Arctic winter 2010/2011 at the brink of an ozone hole
- Large losses of Arctic stratospheric ozone were observed during winter 2010/11
- A further cooling of 1K would have resulted in locally near-complete ozone loss
- A 1K cooling can counterbalance a 10% reduction in halogens
The Arctic stratospheric winter of 2010/2011 was one of the coldest on record with a large loss of stratospheric ozone. Observations of temperature, ozone, nitric acid, water vapor, nitrous oxide, chlorine nitrate and chlorine monoxide from the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) onboard ENVISAT are compared to calculations with a chemical transport model (CTM). There is overall excellent agreement between the model calculations and MIPAS observations, indicating that the processes of denitrification, chlorine activation and catalytic ozone depletion are sufficiently well represented. Polar vortex integrated ozone loss reaches 120 Dobson Units (DU) by early April 2011. Sensitivity calculations with the CTM give an additional ozone loss of about 25DU at the end of the winter for a further cooling of the stratosphere by 1K, showing locally near-complete ozone depletion (remaining ozone < 200ppbv) over a large vertical extent from 16 to 19km altitude. In the CTM a 1K cooling approximately counteracts a 10% reduction in stratospheric halogen loading a halogen reduction that is expected to occur in about 13 years from now. These results indicate that severe ozone depletion like in 2010/2011 or even worse could appear for cold Arctic winters over the next decades if the observed tendency for cold Arctic winters to become colder continues into the future.
Received 23 September 2011; accepted 22 November 2011.
Citation: (2011), Arctic winter 2010/2011 at the brink of an ozone hole, Geophys. Res. Lett., doi:10.1029/2011GL049784, in press.