Tropospheric ozone measurements over Antarctica aboard the NASA DC-8 aircraft are summarized. As part of the August/September 1987 Airborne Antarctic Ozone Experiment, the aircraft flew 13 missions covering a latitude of 53°–90°S, at altitudes to 13 km. Ozone mixing ratios as high as several hundred parts per billion by volume (ppbv) were measured, but in all cases these ratios were observed in pockets or patches of upper atmospheric air. These pockets were observed both in the vicinity of and away from the location of the ozone hole, but they appeared to have occurred with higher frequency near or underneath the ozone hole. At times, and as a result of these pockets, the ozone levels at the flight altitude of the aircraft, as averaged beneath the boundaries of the stratospheric ozone hole, were 2–3 times higher than background tropospheric values. The data suggest that the ozone-rich air seldom penetrated below about 9-km altitude. Background ozone values in the surrounding troposphere were typically in the range of 20–50 ppbv. Correlation of tropospheric ozone observations with the boundaries of the ozone hole differed during the experiment. During the early flights (August 28 through September 2), encounters with ozone-rich air were limited and background tropospheric ozone (at the flight altitude) appeared to decrease beneath the hole. For many of the later flights, and as the hole deepened, the reverse was noted, in that ozone-rich air was frequently observed in the vicinity of the hole and, as noted earlier, average ozone at the flight altitude was frequently higher than background values.
[1]
W. D. Hypes,et al.
Intercomparison of ozone measurements over Antarctica
,
1989
.
[2]
Adrian F. Tuck,et al.
Synoptic and chemical evolution of the Antarctic vortex in late winter and early spring, 1987
,
1989
.
[3]
E. Browell,et al.
Boundary layer ozone - An airborne survey above the Amazon Basin
,
1988
.
[4]
G. Gregory,et al.
Observations of atmospheric ozone: 38° to 76° north latitude at altitudes from 8 km to the surface
,
1984
.
[5]
S. M. Beck,et al.
Measurements of free tropospheric ozone: An aircraft survey from 44° north to 46° south latitude
,
1984
.
[6]
G. Gregory,et al.
Laboratory evaluation of an airborne ozone instrument that compensates for altitude/sensitivity effects.
,
1983,
Environmental science & technology.
[7]
J. A. Ritter,et al.
In situ ozone instrumentation for 10-Hz measurements - Development and evaluation
,
1987
.