New Paper: Cold Arctic winters becoming colder, resulting in large ozone hole

Paper published today notes near-complete loss of ozone over the Arctic due to one of the coldest stratospheric winters on record from 2010-2011. No mention of the now-inconvenient link to man-made chlorofluorocarbon emissions.  

GEOPHYSICAL RESEARCH LETTERS, VOL. 38, L24814, 5 PP., 2011
doi:10.1029/2011GL049784

Arctic winter 2010/2011 at the brink of an ozone hole

Key Points

• 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

B.-M. Sinnhuber

Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology,, Karlsruhe,, Germany

G. Stiller

Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology,, Karlsruhe,, Germany

R. Ruhnke

Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology,, Karlsruhe,, Germany

T. von Clarmann

Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology,, Karlsruhe,, Germany

S. Kellmann

Institute for Meteorology and Climate Research, Karlsruhe Institute of Technology,, Karlsruhe,, Germany

J. Aschmann

Institute of Environmental Physics, University of Bremen,, Bremen,, Germany

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 25 DU at the end of the winter for a further cooling of the stratosphere by 1 K, showing locally near-complete ozone depletion (remaining ozone <200 ppbv) over a large vertical extent from 16 to 19 km altitude. In the CTM a 1 K 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.