瓦里关山大气甲烷本底浓度变化特征的分析

CHARACTERISTICS OF ATMOSPHERIC METHANE CONCENTRATION VARIATION AT MT. WALIGUAN

用气相色谱法在瓦里关全球基准站进行了大气甲烷（ＣＨ４）的连续测量，结合ＮＯＡＡ／ＣＭＤＬ气瓶采样ＣＨ４浓度资料的分析结果，给出了我国内陆高原大气ＣＨ４本底浓度的变化特征．分析结果表明：瓦里关山大气ＣＨ４浓度在１７８０×１０－９～１８４０×１０－９范围内波动，浓度值的变化范围符合中高纬度地区ＣＨ４浓度分布；ＣＨ４浓度有明显的日变化，夏季的变化趋势及振幅与冬春季有所不同；季节变化幅度不大，与全球大气ＣＨ４浓度本底值季节变化的特征及变化幅度的地理分布不太一致；有明显的年际变化，ＣＨ４年平均浓度表现为逐年升高，年增长率的变化与北半球大气ＣＨ４的平均变化趋势基本相符．

By using gas chromatographic method,in situ atmospheric CH 4 was measured continuously at China Global Atmosphere Watch Baseline Observatory at Mt.Waliguan.Combining with FLASK CH 4 data obtained from NOAA/CMDL,the variation features of atmospheric background CH 4 concentration in the inland plateau of China are presented. The results show that the CH 4 concentration at Mt.Waliguan are in the range of 1780×10 -9 ～1840×10 -9 ,it is in accord with the CH 4 distribution in the area of mid and high latitudes. CH 4 concentration at Mt. Waliguan has evident diurnal fluctuation,its pattern and amplitude in summer are different from those in winter and spring;there appears no obvious seasonal variation,and it is dissimilar to the feature of seasonal variation and to the geographical distribution of variation amplitude for global atmospheric CH 4 background concentration. The results also show that there are distinct interannual variations. CH 4 mean annual concentration increases with years and the variations of annual growing rate correspond with the trend of mean variation for atmospheric CH 4 in the Northern Hemisphere.