Stratospheric minor gas distribution over the Antarctic Peninsula during the APE–GAIA campaign
Abstract:This work presents measurements obtained with the multi‐input spectroradiometer GASCOD/A4π, the Fourier transform far‐infrared interferometer SAFIRE‐A and the two‐channel chromatograph HAGAR, on board the M‐55 Geophysica stratospheric aircraft during the APE–GAIA campaign, held in September–October 1999 over the Antarctic Peninsula. The paper aims to investigate the gas mixing ratio distributions at the flight altitude, during a recovery phase of the reservoir species in the lower stratosphere in the Antarctic spring. Attention is focused on the daytime flight of 23 September, when the aircraft flew inside the vortex at two different altitudes (about 16.5km and 18.5km). Concentration distributions were examined for NO 2 , N 2 O, O 3 , BrO, ClO, HCl, H 2 O and HNO 3 , during flight inside and outside the vortex. The NO 2 maxima were well defined in the edge region both on entry into and exit from the vortex at different flight altitudes. Simultaneous concentration measurements of HNO 3 and H 2 O showed a denitrification but not dehydration inside the vortex core. The reformation of chlorine reservoirs is investigated. It was evident that the re‐conversion of HCl was favoured in the Cl+CH 4 branches, and its high mixing ratio up to 1ppbv at 425K surface confirms that low ozone air masses inside the vortex and strong sunlight greatly favour a more rapid formation of passive chlorine reservoirs.
Document Type: Research Article
Affiliations: 1: Institute of Atmospheric Sciences and Climate (ISAC‐CNR), Via Gobetti, 101, 40129 Bologna, Italy 2: IFAC‐CNR, Via Panciatichi, 64, 50127, Florence, Italy 3: University of Aquila, Via Vetoio Località Coppito, 67100 L'Aquila, Italy 4: University of Frankfurt, Senckenberganlage 31, 60325 Frankfurt am Main, Germany
Publication date: 2005-08-20