Airborne arctic stratospheric expedition II: An overview
- Harvard Univ., Cambridge, MA (United States)
- NASA Ames Research Center, Moffett Field, CA (United States)
The sudden onset of ozone depletion in the antarctic vortex set a precedent for both the time scale and the severity of global change. The Airborne Antarctic Ozone Experiment (AAOE), staged from Punta Arenas, Chile, in 1987, established that CFCs, halons, and methyl bromide, the dominant sources of chlorine and bromine radicals in the stratosphere, control the rate of ozone destruction over the Antarctic; that the vortex is depleted in reactive nitrogen and water vapor; and that diabatic cooling during the antarctic winter leads to subsidence within the vortex core, importing air from higher altitudes and lower latitudes. This last conclusion is based on observed dramatic distortion in the tracer fields, most notably N[sub 2]O. In 1989, the first Airborne Arctic Stratospheric Expedition (AASE-I), staged from Stavanger, Norway, and using the same aircraft employed for AAOE (the NASA ER-2 and the NASA DC-8), discovered that while NO[sub x] and to some degree NO[sub y] were perturbed within the arctic vortex, there was little evidence for desiccation. Under these (in contrast to the antarctic) marginally perturbed conditions, however, ClO was found to be dramatically enhanced such that a large fraction of the available (inorganic) chlorine resided in the form of ClO and its dimer ClOOCl. This leaves two abiding issues for the northern hemisphere and the mission of the second Airborne Arctic Stratospheric Expedition (AASE-II): (1) Will significant ozone erosion occur within the arctic vortex in the next ten years as chlorine loading in the stratosphere exceeds four parts per billion by volume (2) Which mechanisms are responsible for the observed ozone erosion poleward of 30[degrees]N in the winter/spring northern hemisphere reported in satellite observations 12 refs., 2 tabs.
- OSTI ID:
- 5058050
- Journal Information:
- Geophysical Research Letters (American Geophysical Union); (United States), Vol. 20:22; ISSN 0094-8276
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
CHLORINE OXIDES
ECOLOGICAL CONCENTRATION
OZONE
ARCTIC REGIONS
ATMOSPHERIC CHEMISTRY
STRATOSPHERE
CHALCOGENIDES
CHEMISTRY
CHLORINE COMPOUNDS
CRYOSPHERE
EARTH ATMOSPHERE
HALOGEN COMPOUNDS
OXIDES
OXYGEN COMPOUNDS
POLAR REGIONS
540120* - Environment
Atmospheric- Chemicals Monitoring & Transport- (1990-)