Late-spring and summertime tropospheric ozone and NO<sub>2</sub> in western Siberia and the Russian Arctic: regional model evaluation and sensitivities

Abstract. We use a regional chemistry transport model (Weather Research and Forecasting coupled with chemistry, WRF-Chem) in conjunction surface observations of tropospheric ozone Ozone Monitoring Instrument (OMI) satellite retrievals column NO2 to evaluate processes controlling the distribution over western Siberia for late spring summer 2011. This region hosts range anthropogenic natural precursor sources, it serves as gateway near-surface Eurasian pollution Arctic. However, there is severe lack situ constrain sources sinks region. show widespread negative bias WRF-Chem when compared OMI from May–August, which reduced using ECLIPSE (Evaluating Climate Air Quality Impacts Short-Lived Pollutants) v5a emissions (fractional mean (FMB) = ?0.82 ?0.73) EDGAR (Emissions Database Global Atmospheric Research)-HTAP (Hemispheric Transport Pollution) v2.2 data (FMB ?0.80 ?0.70). Despite large bias, spatial correlations between observed columns suggest that pattern NOx well represented. Scaling energy inventory by factor 2 reduces ?0.66 ?0.35), but overestimates some urban regions little change persistent underestimate background regions. Based on scaled emissions, we assess influence two dominant emission sectors (transport energy) vegetation fires Russian Our results more sensitive particularly sector, contribution fire maximises June largely confined latitudes south 60? N. dry deposition fluxes simulations sink forest vegetation, averaging 8.0 Tg per month, peaking at 10.3 during June. The impact within domain small negligible north Overall, our controlled an interplay seasonality atmospheric patterns, deposition, dominance sector emissions.