EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Investigation of long-term variation of atmospheric oxidation in background areas of China

Junhua Wang1,2, Baozhu Ge1,2, Bo Yao3, Weili Lin4, Ying Liu5, and Zifa Wang1,2
Junhua Wang et al.
  • 1Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing, China
  • 2University of Chinese Academy of Sciences, Beijing, China
  • 3Meteorological Observation Center of China Meteorological Administration, Beijing, China
  • 4College of Life and Environmental Sciences, Minzu University of China, Beijing, China
  • 5Laboratory for Climate Studies, National Climate Center, China Meteorological Administration, Beijing, China

The atmospheric oxidizing capacity (AOC) is closely related to the self-cleaning ability of the atmosphere in which the air pollutants were removed through reacting with oxidations such as OH radical. The level of OH radical is a dominant indicator to the AOC in clean regions characterized as low levels of NOx which is another factor that influences AOC. Due to a lack of VOCs-related mechanisms in model simulation and high cost of the direct observations of OH radical, the long-term trend of OH radical in China is still unclear, especially under the circumstance of significant reduction of Chinese emissions in recent years. In this study, three methods based on a proxy gas CH3CCl3 from 5 regional background stations in China have been developed to investigate the long-term variation of OH radical in China. The concentration of OH radical in the background area of China is approximately (0.8±0.1)*106 molecular/cm3, lower than the results in other background regions of the world. This could be explained by the larger depletion of OH radical in China due to the higher concentrations of polluted gases (i.e., NOx, CO and CH4). The different methods showed almost consistent results for the long-term trends of OH radical in China. From 2006 to 2017, the annual averaged OH concentration showed a slow downward but insignificant trend with the anomalous annual changes ranging from -0.1% to 0.15%. However, significant inter-annual fluctuations were also detected concurrently with a period about two years. This is consistent with the 2-3 years Quasi-biennial Oscillation (QBO) in the long-term variation of surface O3 concentrations. These results provide the new insights into the annual variation of OH radical in China, which could help improve our understanding of the long-term characteristics of atmospheric oxidation in background areas of China.

How to cite: Wang, J., Ge, B., Yao, B., Lin, W., Liu, Y., and Wang, Z.: Investigation of long-term variation of atmospheric oxidation in background areas of China, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20812,, 2020