Formation of gases and aerosol composition in background and urban areas of Western Siberia: a case study for the record-breaking hot April of 2020

Abstract

Abstract This paper presents results of a comprehensive analysis of the formation of gases and aerosol composition during the anomalously hot April 2020 in Western Siberia. The analysis of the observed change in atmospheric composition and a modeling study with the WRF-Chem is carried out for suburban (TOR-station) and background (FON-station) areas. Two episodes of increased gases and aerosols were detected:13-15 April with a peak on 14 (in most part for the TOR station: increased NO, NO2, CO, CO2, aerosols) and 17-24 April with a peak on 23 (for both stations O3, aerosol, in most part for the FON station: NO2, SO2, CO, and CO2). Atmospheric circulation in the first episode was characterized by mesoscale differences between the two studied locations (surface temperature delta, although both stations are in the same region of large-scale transfers). For the second episode, a large scale atmospheric ridge was observed, which caused a transboundary transfer from Northern Kazakhstan and early wildfires. The simulation with WRF has demonstrated in most cases only the role of wildfires and, in general, has not demonstrated any observed differences between the two episodes. It shows that there is a need to search for more sensitive methods of discovering sources of pollution.