WRF-Chem Modeling of Tropospheric Ozone in the Coastal Cities of the Gulf of Finland

• Published in: Atmosphere
• Main Authors: Georgii Nerobelov, Yana Virolainen, Dmitry Ionov, Alexander Polyakov, Eugene Rozanov
• Format: Article in Journal/Newspaper
• Language: English
• Published: MDPI AG 2024
• Subjects: tropospheric ozone; Gulf of Finland; WRF-Chem modeling; ground-based measurements; FTIR; Meteorology. Climatology; QC851-999; karelia*
• Online Access: https://doi.org/10.3390/atmos15070775; https://doaj.org/article/de752e15c0b04cc4a504ac46ceee9d47

Ozone in the troposphere is a pollutant and greenhouse gas. Atmospheric models can add valuable information to observations for studying the spatial and temporal variations in tropospheric ozone content. The present study is intended to evaluate the variability in tropospheric ozone and its precursors near the Gulf of Finland with a focus on St. Petersburg (Russia) and Helsinki (Finland) in 2016–2019, using the WRF-Chem 3-D numerical model with a spatial resolution of 10 km, together with observations. The diurnal cycle of the near-surface ozone concentrations (NSOCs) in both cities is caused by the variability in NO 2 emissions, planetary boundary layer height, and local meteorological conditions. The seasonal variations in NSOCs and tropospheric ozone content (TrOC) are caused by the variability in total ozone content and in ozone formation in the troposphere. The model reveals a VOC-limited regime in the ~0–1 km layer around St. Petersburg, Helsinki, and the Gulf of Finland and a pronounced NO x -limited regime in the 0–2 km layer in the forests of southern Finland, Karelia, some Russian regions, and the Baltic countries in July. The WRF-Chem model overestimates the measured NSOCs by 10.7–43.5% and the TrOC by 7–10.4%. The observed differences are mainly caused by the errors in chemical boundary conditions and emissions of ozone precursors and by the coarse spatial resolution of the modeling.