Correlations of stratospheric abundances of NOy, O3, N2O, and CH4 derived from ATMOS measurements

Abstract

Correlations are presented for [NOy] relative to [N2O] and [O3] derived from measurements from the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument from a wide range of altitudes and latitudes, including the tropics for which previous analyses have not extended above ∼20 km. Relationships for [O3] versus [N2O] are also given. The results are shown to be in good agreement with aircraft- and balloon-based observations. Distinct correlations are observed for the tropics, the springtime polar vortex, and the extratropics-extravortex regions. These correlations demonstrate rapid production of NOy and O3 in the tropical middle stratosphere and episodic export of air from this region to higher latitudes. Isolation of air within the developing polar vortices in the fall is also shown. Arctic vortex data from April 1993 appear to indicate denitrification of 25-30%, which is evident as a 3.0-4.5 ppb deficit in [NOy] when the vortex [NOy]:[N2O] correlation is compared with the extravortex correlation. A mixture of air descended from above 40 km with air from lower altitudes can fully account for this deficit in [NOy], in addition to approximately half of an apparent Arctic ozone loss of 50-60%, as inferred by comparison of the vortex and extravortex [O3]: [N2O] correlations. Comparison of Antarctic vortex and extravortex correlations from November 1994 similarly show a 60-80% deficit in [NOy] and 80-100% deficit in [O3]; at least half of this apparent denitrification and ozone loss can be attributed to mixing of air descended from higher altitudes with air from lower altitudes. Copyright 1998 by the American Geophysical Union.