Study of CO₂ fluxes for the territoty of SPbU campus

Anthropogenic and natural sources of carbon dioxide emissions into the atmosphere lead to significant climate changes. Modern and reliable methods for measuring greenhouse gas concentrations and fluxes are necessary to monitor greenhouse gases and control the reduction of their emissions in urban areas.

In this study, CO₂ fluxes (FCO₂) were investigated using the eddy covariance method [1] on the territory of the St. Petersburg State University (SPbU) campus (Petrodvorets District, St. Petersburg). Measurements were carried out from August 2023 to July 2024 using an Eddy Covariance System (manufactured by LI-COR), the main components of which are the ultrasonic anemometer uSonic-3 Cage MP and the closed-path gas analyzer LI-7200RS, which records CO₂ and H₂O concentrations. To assess pollution levels and sources, average CO₂ fluxes were analyzed for the year period and separately for each month. Additionally, their variations were examined in relation to changes in temperature, wind direction, and speed. A diurnal cycle of CO₂ fluxes was plotted for each month.

The study obtained an average CO₂ flux value for the entire observation period: 1.95 μmol*m⁻²·s⁻¹. Daily variations in CO₂ fluxes were also investigated, we obtain that the minimum of average FCO₂ recorded at -2.37 μmol·m⁻²·s⁻¹ in June 2024 at 09:30 UTC, and the maximum at 5.92 μmol·m⁻²·s⁻¹ in December 2023 at 12:00 UTC.

Based on our analysis, the dependence of CO₂ fluxes on the vegetation period was confirmed.

Funding and acknowledgments:
This research was supported by the SPbU project "From a Carbon Polygon to Carbon Regulation: The Potential and Development Pathways of the Carbon Sequestration Industry in the Leningrad Region and St. Petersburg" (GZ_MDF_2023 - 3, Pure ID 132271892). The study used equipment from the "Geomodel" Research Center of the SPbU Science Park.

References:
1. Eddy Covariance Method: A Brief Practical Guide; Burba G.G., Kurbatova Yu.A., Kuricheva O.A., Avilov V.K., Mamkin V.V., 2016.