Abstract

In situ, N₂O measurements were made using a laser absorption spectrometer, ATLAS, on twelve flights into the Antarctic vortex as well as on five transit flights outside the vortex region in Aug. and Sept. 1987 as part of the airborne Antarctic ozone experiment. Vertical profiles of N₂O were obtained within the vortex on most of these flights and outside the vortex on several occasions. Flights into the vortex region show N₂O decreasing southward between 53°S and 72°S latitude on constant potential temperature surfaces in the lower stratosphere. The data lead to two important conclusions about the vortex region: (1) The lower stratosphere in Aug./Sept. 1987 was occupied by old air, which had subsided several kilometers during the polar winter; (2) the N₂O profile in the vortex was approximately in a steady state in Aug./Sept. 1987, which indicates that the spring upwelling, suggested by several theories, did not occur.

© 1988 Optical Society of America