Methane Variability in the Surface Atmospheric Layer at a Background Forest Station in the Prioksko-Terrasny Reserve

The paper presents the methodology, results, and analysis of routine methane measurements in the atmospheric surface layer at a remote integrated background monitoring station in the Prioksko-Terrasny Biosphere Reserve (PTBR). The analysis of seasonal variability in atmospheric methane over the background area, the quantification of its changes and a trend for the entire observation period (2006–2020) are provided. According to long-term data, there is a summer minimum of averaged methane concentrations in the annual cycle, while the maximum is observed in winter. The mean methane level at PTBR is 5–10% higher than global mean background methane concentrations. An evaluated linear trend toward the methane growth at the PTBR is 2 ppb per year, which is lower than the global mean rate.