An analysis of the distribution of nitrogen dioxide in the south-eastern Mediterranean for the period 1985–1989

Abstract

The abundance of ozone in the stratosphere depends upon a photochemical cycle in which nitrogen dioxide ( N0₂) plays a predominant role. Although the zonal mean cross-sections for N0₂ averaged for 34 months have been calculated–on the basis of L1MS data–lack of detailed information at local or regional scale could result in difficulties in terms of modelling the distribution of ozone in the stratosphere. In this paper we use SAGE II measurements to calculate the altitude profiles of N0₂ mixing ratios for the geographical region 15 to 30° E and 32·5 to 42·5° N for the period 1985 to 1989.Analysis of the findings shows that N0₂ experiences higher values in summer months, that the N0₂ maximum mixing ratios decrease from 1985 to 1989, that maximum mixing ratios are found at an altitude ofapproximately 33 km, with variations depending on season and year and that N0₂ mixing ratios for the period 1985–1989 are higher compared to the relevant mixing ratios for 1979–1981.