MERIDIONAL DISTRIBUTIONS OF NO(X), NO(Y) AND OTHER SPECIES IN THE LOWER STRATOSPHERE AND UPPER TROPOSPHERE DURING AASE-II

The meridional distribution of NO(x) in the lower stratosphere and upp er troposphere is inferred from 10 flights of the NASA DC-8 in the nor thern winter of 1992, along with like distributions of NO(y), NO(x)/NO (y), CO, and C2Cl4. In the lowest few km of the stratosphere there is little vertical gradient in NO(x) over the range of latitudes measured (40-degrees-90-degrees-N). There is a substantial latitudinal gradien t, with 50 pptv above the pole and 120 pptv near 40-degrees-N. In the uppermost few km of the troposphere, background values range from 30 p ptv over the pole to 90 pptv near 40-degrees-N. On two occasions highe r values, up to 140 pptv in the mean, were seen 2-3 km below the tropo pause in association with frontal systems. The meridional distribution s of CO and C2Cl4 show the same feature, suggesting that the source of the elevated NO(x) is near the earth's surface.