Altitude distribution of stratospheric NO3. 1. Observations of NO3 and related species

Abstract : Five balloon‐borne observations of the vertical profile of stratospheric NO3 and ozone were performed between 1981 and 1985 by using the star and planet occultation technique at 662 nm. During the last two flights, NO2 was also measured by the same technique at 440 nm. The latest available laboratory determination of the 662‐nm absorption cross section of NO3 has been used for the data analysis. This gives NO3 concentrations that are about a factor of 2 lower than those previously reported. The concentration of NO3 increases with altitude, from about 1×107 molecules cm−3 around 22 km, to 2×107 molecules cm−3 at 38 km in September. A maximum value of 4×107 molecules cm−3 was observed at 38 km in May 1982. Ozone and NO2 results obtained from the same flights as NO3 are also presented. A companion paper provides details on the comparison between observed and modeled NO3 vertical profiles.