The Determination of Stratospheric Nitrogen Dioxide Concentrations from Limb Brightness Measurements Made from a Balloon Platform.

The role of nitrogen dioxide in the maintenance of photochemical equilibrium in the stratospheric ozone layer is now fairly well understood. However, there are some questions remaining concerning the global distribution and diurnal variation of nitrogen compounds which can be quantified only through the study of accurate vertical profile data. Valuable data on the amount and distribution of nitrogen dioxide have been obtained through the use of the visible light solar occultation technique. Since these data can only be gathered during the day/night transition period, comparisons to models, which do not model this period well, are somewhat problematical. It is therefore useful to extend the visible light spectroscopic measurement into the daytime period through the development of a limb scanning instrument for the observation of daytime NO(,2) amounts. A time multiplexed spectrophotometer was developed to make light intensity observations of the limb of the earth in five narrow bands in the blue region of the spectrum (438 to 450 nm). These observations were interpreted through the application of an atmospheric inversion algorithm to yield data on the vertical distribution of nitrogen dioxide gas in the daytime stratosphere. The inversion algorithm is based on a single scattering model which was developed to predict the spectrophotometer's response to changes in the composition of the sunlit atmosphere. Observations of the atmosphere made in June 1983 from Palestine, Texas were analysed to produce a vertical profile of NO(,2).