【摘要】 甲烷是二氧化碳之后的第二大温室气体,减少甲烷排放是政府间气候变化专门委员会报告中的关键焦点.目前,大气中的甲烷通过依赖光谱特性的地面观测和卫星遥感来监测.然而,广泛使用的HITRAN数据库提供的甲烷谱线位置缺乏准确检索所需的精度.本文使用腔增强吸收光谱法测量了1.66μm处甲烷大气检测窗口附近的饱和吸收光谱.从多普勒展宽的甲烷吸收线上观测到的饱和吸收峰中,确定了谱线位置,其绝对频率精度优于2 MHz.结果还表明,HITRAN数据库和基于从头算计算的甲烷线的理论模型在这一区域的结果都不是很好.更多还原

【Abstract】 Methane is the second most important greenhouse gas after carbon dioxide,and the reduction of methane emissions is a key focus in IPCC reports.At present,atmospheric methane is monitored through ground-based observations and satellite remote sensing that depend on spectral characteristics.However,the positions of the methane lines provided by the widely utilized HITRAN database lack the precision required for accurate retrievals.In this work,we used cavity-enhanced absorption spectroscopy to record the absorption spectrum near the atmospheric detection window of methane at 1.66 μm.From the saturated absorption peaks( "Lamb dips") observed on top of Doppler-broadened methane absorption lines,we determined the line positions with an absolute frequency accuracy of better than 2 MHz.The results also indicate the incompetence of the HITRAN database and theoretical models based on ab initio calculations of methane lines in this region.更多还原