Trend and seasonal variations of atmospheric CH_4 in Beijing

Article type: Research Article

Authors: Wang, Yue-si | Wang, Ming-xing | Luo, Dong-mei | Zheng, Yun-hua | Zhou, Li

Affiliations: Institute of Atmospheric Physics, Chinese Academy of Sciences, Beijing 100029, China

Abstract: The atmospheric CH_4 in Beijing is still increasing, even though its increasing rate has significantly decreased from 1.76 %/a during 1985-1989 to 0.50 %/a during 1990-1997. The seasonal variation of CH_4 concentration showed a double-peak pattern, one peak appearing in winter and the other in summer. It is evident that the annually seasonal variations of atmospheric CH_4 in Beijing are different. From 1986 to 1997, the atmospheric CH_4 increased by 185 ppbv, 37% and 21% of which were due to the increase in winter and in summer, respectively. After 1993, the annually seasonal increasing rate of CH_4 concentration in summer (due to emission from biogenic sources) is negative while the increasing rate in winter (due to emission from non-biogenic sources) is positive about 25 ppbv/a. As a result, the increase of CH_4 emission from non-biogenic sources in winter is the major reason that caused theannually seasonal increasing rate from 1993 to 1997. The biogenic sources in Beijing are shrinking while the non-biogenic ones (such as fossil fuel combustion) are enlarging.

Keywords: atmospheric CH_4, increasing rate, seasonal variation, annually seasonal variation

Journal: Journal of Environmental Sciences, vol. 12, no. 3, pp. 369-374, 2000