Balloon observation of the vertical profile of the stratospheric NO2

The vertical profile of stratospheric NO2 was studied with a monochromator set on a balloon. The solar spectra of wave length between 427 and 451 nm were observed. The balloon flight was made on May 29, 1978. The observation was performed at the altitude of 24 km. The amount of NO2 was determined by the statistical analysis of absorption spectra. The standard spectrum for the analysis was that obtained at 24 km altitude and 35 degree of solar zenith angle. Dependence of the amount of NO2 on the solar zenith angle was measured, and the vertical profile was estimated. The maximum density of NO2 was about 3.7 x 109 molecule/cm3, the density at 35 km altitude was about 1.3 x 109 molecule/cm3, and that at 14 km altitude was 1.1 x 109 molecule/cm3. The obtained profile was in good agreement with other reports in the region of visible light, but was twice as large as the results by the infrared observation. (Kato, T.)