Maintenance of high HCl/Clyand NOx/NOy, in the Antarctic vortex: A chemical signature of confinement during spring
| Autor: | Hope A. Michelsen, James M. Russell, C. M. Spivakovsky, Fredrick W. Irion, James J. Margitan, Christopher R. Webster, Gloria L. Manney, M. R. Gunson, D. C. Scott, R. D. May |
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| Rok vydání: | 1999 |
| Předmět: |
Atmospheric Science
Ozone Ecology Paleontology Soil Science Flux Forestry Aquatic Science Oceanography Atmospheric sciences Vortex Atmosphere chemistry.chemical_compound Geophysics chemistry Space and Planetary Science Geochemistry and Petrology Polar vortex Atmospheric chemistry Earth and Planetary Sciences (miscellaneous) Nitrogen oxide Stratosphere Earth-Surface Processes Water Science and Technology |
| Zdroj: | Journal of Geophysical Research: Atmospheres. 104:26419-26436 |
| ISSN: | 0148-0227 |
| DOI: | 10.1029/1999jd900473 |
| Popis: | Observations made in the 1994 Antarctic vortex show that Cl y recovered completely into HCl following conversion of Cl y reservoir species to active radicals, and NO x constituted a 4-5 times higher fraction of NO y inside the vortex than outside. Measurements made in October and November from the Airborne Southern Hemisphere Ozone Expedition/Measurements of the Atmospheric Effects of Stratospheric Aircraft (ASHOE/MAESA) ER-2 aircraft mission, the third Atmospheric Laboratory for Applications and Science (ATLAS-3) space shuttle mission, and the Upper Atmosphere Research Satellite (UARS) demonstrate that this unusual partitioning of Cl y and NO y was maintained for at least 4 weeks in the springtime vortex. In response to severe ozone loss, abundances of HCl and NO x remained high despite temperatures low enough to reactivate Cl y and convert NO x to HNO 3 via heterogeneous processes. Thus, under severely ozone depleted conditions, high HCl and NO x abundances in the vortex are maintained until the vortex breaks up or an influx of ozone-rich extravortex air is entrained into the vortex. These observations suggest that the flux of extravortex air entering the core of the lower stratospheric vortex was small or negligible above ∼400 K during late spring, despite weakening of the vortex during this time period. Results of a photochemical model constrained by the measurements suggest that extravortex air entrained into the vortex during October and early November made up less than 5% of the vortex core air at 409 K. The model results also show that heterogeneous chemistry has little effect on the Cl y and NO y partitioning once high abundances of HCl have been attained under ozone depleted conditions, even when aerosol loading is high. |
| Databáze: | OpenAIRE |
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