Airborne antarctic ozone experiment (AAOE-87): ER-2 & DC-8 aircraft mission To investigate antarctic ozone in late winter 1987: overview
Recent observations have shown since 1979 a dramatic and unexpected downward trend in the overhead column abundance of ozone during late winter and early spring over Antarctica, at the Halley Bay and Argentine Islands stations (76 degrees S, 27 degrees W and 65 degrees S, 64 degrees W). The reductio...
| Main Authors: | , |
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| Format: | Book |
| Language: | English |
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National Aeronautics and Space Administration (NASA)
1989
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| Online Access: | http://cedadocs.ceda.ac.uk/57/ http://cloud1.arc.nasa.gov/aaoe/project/overview.html http://cedadocs.ceda.ac.uk/57/1/overview.txt |
| Summary: | Recent observations have shown since 1979 a dramatic and unexpected downward trend in the overhead column abundance of ozone during late winter and early spring over Antarctica, at the Halley Bay and Argentine Islands stations (76 degrees S, 27 degrees W and 65 degrees S, 64 degrees W). The reduction, amounting by 1985 to about 40% of the historical October monthly mean, has been confirmed and given a geographically mapped perspective by observations from NASA's Total Ozone Mapping Spectrometer (TOMS) on Nimbus 7. Ozonesonde ascents from Syowa station (69 degrees S, 40 degrees E) in 1982 and 1983 have shown that in October, before the final warming, ozone is depleted by between 10% and 50% at altitudes between about 10 and 22 km, compared to values observed in the late 1960's and early 1970's. The chemical data base has been considerably enhanced by the observations taken from late August to the beginning of November 1986 from McMurdo Base (78 degreees S, 167 degrees E) by the National Ozone Expedition (NOZE), which was organized by NSF. Ozone profiles, 33 in number distributed fairly evenly between 25 August and 6 November, confirmed the picture suggested by the Syowa data, and showed considerable vertical structure in the mixing ratio, particularly during October. It was clear that the ozone loss over McMurdo developed during September. Further, as yet unpublished, observations of the column abundances of O3, NO2, and OC1O by the NOAA Aeronomy Lab, of HCl, ClONO2 and HNO3 (inter alia) by JPL and observations of N2O and C1O by SUNY which contain some coarse information about altitude distribution, should all have a substantial impact on knowledge of the photochemical balance, and its interpretation. The NOAA data Show evidence of very unusual odd nitrogen chemistry (very low abundance and very small diurnal variation of NO2 and of unusual chlorine chemistry (high abundance of OC1O). |
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