Comparison of Atmospheric CO2, CH4, and CO at Two Stations in the Tibetan Plateau of China

Abstract

The research of greenhouse gases on the Tibetan Plateau is of great importance since its unique topography as the third pole of our planet and profound response on the climate change. In this study, we compared the concurrent observations of atmospheric carbon dioxide (CO2), methane (CH4), and carbon monoxide (CO) during 2010–2016 from two stations located on the Tibetan Plateau, which are Mt. Waliguan station (WLG), the only World Meteorological Organization/Global Atmosphere Watch global station in the inland of Eurasia, and Shangri-La station, a Chinese national station (XGLL). Although both stations are located at remote area, the atmospheric CO2, CH4, and CO concentrations are frequently influenced by regional sources, especially for XGLL throughout the year and WLG in summer. Due to the unique topography and regional conditions, the atmospheric CH4 and CO at both stations display different trends with other sites in China, with higher values in summer. The atmospheric CO2, CH4, and CO at the XGLL mainly represent the conditions in regional scale. As the only World Meteorological Organization/Global Atmosphere Watch global station in the inland of Eurasia, the observation results at WLG can be used to represent the conditions on the Tibetan Plateau, but some of them are frequently influenced by the emissions from the cities located on the east or north east, and some even can be affect by emissions from the Ganges basin in autumn and winter, which should be treated with caution. By subtracting the influences of the cities, we updated the growth rate of 2.45 ± 0.02 ppm yr−1 for CO2, 8.2 ± 0.1 ppb yr−1 for CH4, and −0.4 ± 0.1 ppb yr−1 for CO, compared to the prior estimation of 2.31 ± 0.02 ppm yr−1 for CO2, 8.1 ± 0.1 ppb yr−1 for CH4, and −0.6 ± 0.1 ppb yr−1 for CO on the Tibetan Plateau.