HALOE observations of polar stratospheric clouds in the Antarctic in October 1993

Measurements by the Halogen Occultation Experiment (HALOE)during the austral spring of 1993 show anomalously high aerosol extinction profiles over the Weddell Sea on October 7 - 9. With temperatures falling to 195 K and below, conditions were favorable for the formation of polar stratospheric clouds (PSCs). Geopotential height fields from the United Kingdom Meteorological Office (UKMO) meteorological analyses suggest that the region of cold temperatures was being influenced by flow patterns in the midtroposphere. HALOE measurements of methane and water vapor mixing ratio, together with potential vorticity maps and wind fields from the UKMO analyses, suggest there was transport of mid-latitude air to polar latitudes. (C) 1999 COSPAR. Published by Elsevier Science Ltd.