Ten years of atmospheric methane observations at a high elevation site in Western China
Ten years of atmospheric methane observations at a high elevation site in Western China
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DOI：
10.1016/j.atmosenv.2004.02.072
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发表时间：
2004-12
影响因子：
5
通讯作者：
Ling-xi Zhou;D. Worthy;P. M. Lang;M. Ernst;Xiangyu Zhang;Y. Wen;Jing Li
中科院分区：
文献类型：
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作者：
Ling-xi Zhou;D. Worthy;P. M. Lang;M. Ernst;Xiangyu Zhang;Y. Wen;Jing Li
本文介绍了位于中国西部（36°17′N，100°54′E，3816 masl）的瓦里关基线观测站1994-2001年和1991-2001年大气CH 4的连续和离散采样观测结果。CH 4时间序列显示，全年发生的大事件数量级为100 ppb。在春季，一个日周期的平均振幅为7 ppb，上午最大，下午晚些时候最小。在冬季，观测到平均振幅为14 ppb的日变化周期，下午最大，上午最小。与大多数陆地观测站不同，在夏季或秋季没有明显的昼夜模式。一个背景数据选择程序的基础上，当地的水平和垂直风。代表“基线”条件的选定每小时数据集由约50%的有效每小时数据得出。1992-2001年期间瓦里关的CH 4混合比、年平均值、年增长率和平均年周期的范围来自代表“基线”条件的离散和连续数据，并与在其他北方半球站点收集的空气样品进行比较。瓦里关甲烷的月平均值为1746- 1822 ppb，年平均值为1786.7±10.8ppb，年平均增加值为4.5±4.2ppbyr-1，与30° ~ 60°N的观测结果一致。有变化，观察到在瓦里关的CH 4的年增长模式，这是从全球模式略有不同。瓦里关甲烷年循环的平均峰-峰振幅为1.11ppb，比大多数中高纬度地区小得多，表现为夏季和2月沿着出现两个平缓的峰，冬初和春季出现两个小的谷。瓦里关CH 4数据受亚洲大陆CH 4排放的影响很大，为全球大气CH 4模式提供了关键信息。
In this paper, the continuous (1994–2001) and discrete air sample (1991–2001) measurements of atmospheric CH4from the Waliguan Baseline Observatory located in western China (36°17′N, 100°54′E, 3816masl) are presented and characterized. The CH4time series show large episodic events on the order of 100ppb throughout the year. During spring, a diurnal cycle with average amplitude of 7ppb and a morning maximum and late afternoon minimum is observed. In winter, a diurnal cycle with average amplitude of 14ppb is observed with an afternoon maximum and morning minimum. Unlike most terrestrial observational sites, no obvious diurnal patterns are present during the summer or autumn. A background data selection procedure was developed based on local horizontal and vertical winds. A selected hourly data set representative of “baseline” conditions was derived with approximately 50% of the valid hourly data. The range of CH4mixing ratios, annual means, annual increases and mean annual cycle at Waliguan during the 1992–2001 were derived from discrete and continuous data representative of “baseline” conditions and compared to air samples collected at other Northern Hemisphere sites. The range of CH4monthly means of 1746–1822ppb, average annual means of 1786.7±10.8ppb and mean annual increase of 4.5±4.2ppbyr−1at Waliguan were inline with measurements from sites located between 30° and 60°N. There were variations observed in the CH4annual increase patterns at Waliguan that were slightly different from the global pattern. The mean CH4annual cycle at Waliguan shows an unusual pattern of two gentle peaks in summer and February along with two small valleys in early winter and spring and a mean peak-to-peak amplitude of ∼11ppb, much smaller than amplitudes observed at most other mid- and high-northern latitude sites. The Waliguan CH4data are strongly influenced by continental Asian CH4emissions and provide key information for global atmospheric CH4models.