Geographical variations of NO and O3 in the lower stratosphere

Nitric oxide and ozone concentrations in the lower stratosphere have been measured from a high‐altitude research aircraft using in situ measuring techniques. Results of several geographical surveys are presented along with predictions of two two‐dimensional stratospheric models. Meridional and zonal data were obtained in June 1974 and in June, July, and August 1975. At longitudes 122°–158°W the meridional data taken between 5° and 80°N latitude show an increasing NO concentration with latitude, by a factor of 4 at 21‐km altitude and a less marked increase at 18 km. The minimum NO concentration at 21 km is observed at 5°N latitude and is about 6 × 108 cm−3. Zonal data at latitudes 22°–38°N taken from 55° to 176°N longitude show little variation of the NO and O3 concentrations with longitude.