Atmospheric Chemistry and Physics Discussions www.atmos-chem-phys-discuss.net 1680-7367 1680-7375 6 6 2006 10.5194/acpd-6-11391-2006 http://www.atmos-chem-phys-discuss.net/6/11391/2006/ http://www.atmos-chem-phys-discuss.net/6/11391/2006/acpd-6-11391-2006.html http://www.atmos-chem-phys-discuss.net/6/11391/2006/acpd-6-11391-2006.pdf 11391 11426 2006-11-16 Observations and analysis of polar stratospheric clouds detected by POAM III and SAGE III during the SOLVE II/VINTERSOL campaign in the 2002/2003 Northern Hemisphere winter J. Alfred M. Fromm R. Bevilacqua G. Nedoluha A. Strawa L. Poole J. Wickert Computational Physics Inc., Springfield VA, USA Naval Research Lab, Remote Sensing Division, Washington D.C., USA NASA Ames Research Center, Atmospheric Physics Branch, Moffett Field CA, USA Science Applications International Corporation, Hampton VA, USA GeoForschungsZentrum, Dept. Geodesy and Remote Sensing, Potsdam, Germany The Polar Ozone and Aerosol Measurement and Stratospheric Aerosol and Gas Experiment instruments both observed high numbers of polar stratospheric clouds (PSCs) in the polar region during the second SAGE Ozone Loss and Validation Experiment (SOLVE II) and Validation of INTERnational Satellites and Study of Ozone Loss (VINTERSOL) campaign, conducted during the 2002/2003 Northern Hemisphere winter. Between 15 November 2002 (14 November 2002) and 18 March 2003 (21 March 2003) SAGE (POAM) observed 122 (151) aerosol extinction profiles containing PSCs. PSCs were observed on an almost daily basis, from early December through 15 January, in both instruments. No PSCs were observed from either instrument until 4 February, and sparingly in three periods in mid-and-late February and mid-March. In early December, PSCs were observed in the potential temperature range from roughly 375 K to 750 K. Throughout December the top of this range decreases to near 600 K. In February and March, PSC observations were primarily constrained to potential temperatures below 500 K. The PSC observation frequency as a function of ambient temperature relative to the NAT saturation point was used to infer irreversible denitrification. By late December 38% denitrification was inferred at both the 400–475 K and 475–550 K potential temperature ranges. By early January extensive levels of denitrification near 80% were inferred at both potential temperature ranges, and the air remained denitrified at least through early March.