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Abstract
The Arctic winter 2007–08 was characterized by cold temperatures and a strong vortex. Potentials for large areas of ice and Polar Stratospheric Clouds (PSCs) are observed during the winter. A vortex wide denitrification (removal of 60–80% of NO y ) and intense chlorine activation (0.6 to 1.05 ppb of ClO) are found inside the vortex at 475 K. This chemical morphology triggered a high rate of ozone loss during the winter. The simulated results from MIMOSA-CHIM show a large loss of ozone at 425–550 K from January to March, about 1.5–2.3 ppm. The vortex averaged loss at 475 K is about 2.5 ppm in mid-March, which is in very good agreement with the estimated loss (2.3 ppm) from the Microwave Limb Sounder (MLS) measurements. Similar analyses from MIMOSA-CHIM for recent winters show a cumulative loss of 2.1 ppm in 2006–07 and 2.0 ppm in 2004–05 in tune with the measurements. The measured and simulated results show the highest loss in 2007–08 in comparison with the analyses for the last four winters at 475 K.
Acknowledgements
The authors would like to thank Julien Gazeaux and Cathy Boonne of Service d'A`eronomie/IPSL/CNRS for their assistance with the simulations. The ECMWF analyses are taken from the NILU database. The work is supported by funds from the ANR/ORACLE-O3 France and the EU SCOUT-03 projects. The MLS data used in this study were acquired as part of NASA's, Earth-Sun System Division and archived and distributed by the Goddard Earth Sciences (GES) Data and Information Services Center (DISC).