Altitude Distribution of Nitrogen Dioxide in the Volga Federal District

Abstract

The purpose is to study the features of the altitude distribution of NO2 in the troposphere and stratosphere of the Volga Federal District (VFD) for the period 2003-2023.Materials and methods. The multi-level data of the CAMS (EAC4) global re-analysis of VFD for the period under consideration served as initial data. Results and discussion. The seasonal variation of the NO2 content in the troposphere and stratosphere was analyzed, and a trend analysis was carried out. Conclusions: 1. The average NO2 content is maximum near 1000 hPa (12700 ppt), sharply decreasing with increasing altitude (≤ 38 ppt per 18 km). Around 10 hPa, growth is observed (up to 5900 ppt). In the 5-1 hPa layers, it decreases again (≤ 124 ppt). 2. The seasonal variability of NO2 manifests itself to varying degrees at diff erent baric levels: at 1000-700 hPa, the maximum average NO2 content is observed in winter-spring, the minimum in summer; at 500-200 hPa, the maximum is noted in winter, the minimum in spring; in the 100-10 hPa layer, the maximum is revealed in spring-summer, the minimum in winter; at 7-1 hPa, the maximum NO2 concentration is observed in autumn, and the minimum in spring-summer. 3. Near the ground there is a signifi cant accumulation of NO2 in summer up to 830 ppt/10 years. In winter, there is a signifi cant trend of impurity dispersion >1110 ppt/10 years in the southern and southeastern regions of the Volga Federal District. Above 9 km, a signifi cant trend towards NO2 accumulation was recorded during the spring-summer period. Thus, at the level of 10 hPa in May, the SCLT reached 256,5 ppt/10 years. No signifi cant NO2 trends were detected in the autumn-winter period.