Variations of background atmospheric methane at Mt.Waliguan, China
瓦里关山大气CH4本底变化

By using observational data during the period of May 1991-May 2002 at Waliguan Observatory(36°17'N, 100°54'E, 3816m asl), characteristics of background atmospheric CH4 as well as potential relationship between sources and sinks, were studied.Results indicated that, the CH4 concentration distribution and the growth trend coincided with the results of other monitoring records in the similar latitudinal band 60°N-30°N.However, the averaged seasonal variation pattem of CH4 and amplitude has a notable discrepancy according to the station's geographical location.The fluctuation of CH4 annual growth values did not reach the global means.The unique CH4 characteristics at Waliguan are probably attributed to the joint influence of multiple sources, sinks, as well as air mass transport from the surrounding areas.The observational data of CH4 obtained at Waliguan represents the Asian continental behavior with global representativeness.It can further explain the formation of background CH4 characteristics in the inland plateau of China by combining with other relevant information.