Background characteristics and influence analysis of greenhouse gases at Akedala regional background station in Northern Xinjiang

Abstract

Based on the weekly collected flask air samples at Akedala (AKD) Station in northern Xinjiang during 2009–2020, we measured the concentrations of CO2, CH4 and CO and analyzed their long-term variation trend, seasonal characteristics and the influence mechanism of anthropogenic and long-range transport of greenhouse gases at the background station. The results revealed that the background concentrations of CO2 and CH4 at the station experienced an upward trend, while that of CO gradually declined. The CO2 and CH4 background concentrations were 415.69 ± 6.14 ppm and 1976.88 ± 22.26 ppb, respectively, in 2020. The growth rates were 2.41 ppm y−1 and 8.40 ppb y−1 for CO2 and CH4, respectively, during 2009–2020. The background concentration of CO was 128.35 ± 14.83 ppb in 2019 and experienced a downward trend at an average rate of −0.13 ppb y−1 during 2009–2019. The concentrations of CO2, CH4 and CO were all highest in winter. The analysis of the backward trajectory and potential source contribution function revealed the natural and anthropogenic emissions from eastern Kazakhstan, southern Russia, and northern Xinjiang were the main contributors to greenhouse gases concentrations at AKD stations. Moreover, local sources influencing AKD Station were found to be mainly in the southwest direction in winter, reflecting the large anthropogenic emissions in these directions. The results presented here can support a better understanding of the regional/local characteristics of greenhouse gases in the atmosphere of northern Xinjiang against the influence of regional transport, as well as background observations of greenhouse gases in northwestern China and Central Asia.