空气CH4浓度变化及其与CO的相关性

CH4是一种重要的温室气体,在空气中的含量仅次于CO2.化合物之间的相关性在化合物的浓度测量和估算等方面都有重要的意义.通过分辨率为1 cm-1的长开放光路傅里叶变换红外光谱仪测量采样路径内的北京西四环高速公路附近空气CH4和CO透过率光谱,进行非线性最小二乘光谱拟合,计算出待测组分浓度.北京秋季空气CH4浓度变化趋势几乎一样.白天的浓度变化趋势表明城市中人为活动对CH4的排放影响极大,尤其是机动车尾气的排放,而晚上浓度主要是近地面的积累.2005年9月4日到2005年9月10日的连续浓度变化表明北京秋季每天CH4和CO浓度变化趋势相同,它们的浓度变化具有一定的相关性.

Atmospheric CH4 Concentrations and the Correlation between CH4 and CO Concentrations

Methane (CH4) is an important greenhouse gas and a key molecule in tropospheric photochemistry, some more potent than CO2. The remote-sensing experiments of CH4 were carried out in the fall of 2 000 in Beijng. The 6-day records of the atmospheric CH4 concentrations were examined by means of a time-series analysis using a fast Fourier transform with a low-pass filter to elucidate the seasonal cycles and the long-term trends. The variation in the long-time trends of the CH4 concentrations in Beijing may be ascribed to the emission changes in the CH4 sources due to the human activities such as waste dumping and landfills and the emission from motor vehicles. The correlation between the CH4 and CO concentrations was analyzed.