Soil-Atmosphere Greenhouse Gas Fluxes in a Background Area in the Tomsk Region (Western Siberia)

The dynamics of greenhouse gas fluxes, measured from 2017 to 2021 at the Fonovaya Observatory of V.E. Zuev Institute of Atmospheric Optics, Siberian Branch, Russian Academy of Sciences, is studied. It is shown that the annual average fluxes of CO2 at the Observatory varied from -283 (sink) to +31 mg m(-2) h(-1) (emission). A minimal emission of 1351 mg m(-2) h(-1) was recorded in 2019, and a maximum of 1789 mg m(-2) h(-1), in 2021. The lowest sink was observed in 2017 (2099 mg m(-2) h(-1)); the largest, equal to 2304 mg m(-2) h(-1), was in 2018. The annual average methane fluxes ranged from -0.032 in 2018 to -0.047 mg m(-2) h(-1) in 2020. The daily maximal methane emission was recorded in 2018 and was equal to 0.915 mg m(-2) h(-1), and the daily minimal emission, in 2021 (0.095 mg m(-2) h(-1)). The maximal sink varied from year to year in a narrower range from -0.241 to -0.361 mg m(-2) h(-1). The soil of the measurement area turned out to be a strong source of SO2 and CH4 and a weak source of N2O. The annual average fluxes of NO2 were in the 0.00-0.011 mg m(-2) h(-1) range. The interannual emission maxima weakly changed from 0.237 to 0.301 mg m(-2) h(-1), and sink maxima, from -0.206 to -0.245 mg m(-2) h(-1).