改进的大气CO_2、CH_4、N_2O、CO在线观测FTIR系统  

Study on the in-situ Measurement of Greenhouse Gas by an Improved FTIR

作　　者：夏玲君[1,2] 刘立新[1] 周凌晞[1] 方双喜[1] 王红阳[1] 张振波[1] 

机构地区：[1]中国气象科学研究院,北京100081 [2]南京信息工程大学大气物理学院,南京210044

出　　处：《环境科学》2013年第11期4159-4164,共6页Environmental Science

基　　金：国家重点基础研究发展规划(973)项目(2010CB950601);国家自然科学基金项目(40905066;41175116;41273097);科技部国际合作项目(2011DFA21090);中国气象局气象关键技术集成与应用项目(CMAGJ2012M77;CMAGJ2013M73)

摘　　要：利用商用傅利叶变换红外光谱仪(FTIR)主机,与自动进样模块及标气模块集成,初步建立了一套可流程化、准确、高效分析大气CO2、CH4、CO和N2O的在线观测系统.测试结果表明,该商用FTIR主机具有良好的精度,但以仪器自带校正系数估算的结果绝对误差大,尤其CO的绝对误差可达38.8×10-9,无法满足在线观测要求.集成后的FTIR系统改用可溯源至国际标准的工作标气进行计算,有效降低了结果的绝对误差.动态及静态两种模式下各要素实测值与标称值的摩尔分数绝对误差为CO2≤0.11×10-6、CH4≤1.8×10-9、N2O≤0.15×10-9、CO≤0.5×10-9,能够满足大气在线观测需求.利用该FTIR集成系统进行6 d的模拟在线观测,采用动态流量模式(Flow)进样,每隔6 h穿插高、低浓度工作标气及目标气进样,用标气的标称值及系统更新的标气响应值计算样气及目标气结果.目标气CO2/CH4/N2O/CO的摩尔分数标准偏差分别为0.05×10-6、0.2×10-9、0.07×10-9、0.5×10-9,平均值与标称值之间的绝对误差分别为0.09×10-6、0.4×10-9、0.14×10-9、0.5×10-9.The real-time, automatic, highly accurate and efficient system for measuring the mixing ratios of CO2 , CH4 , CO and N2O has been developed by combining the commercial FTIR system （Wollongong University） with an auto-sampling system and a working standard module. Based on the tests conducted, the FTIR showed the high precision and a relatively low accuracy associated with its poor determination of correction factors. The absolute error of the mixing ratio of CO was above 38.8 × 10-9, suggesting that FTIR alone could not meet the requirement for the real time measurement. Using the working standard gases to adjust results from the FTIR significantly improved the accuracy of measurements. For both static and dynamic conditions, the discrepancies between the measured results and the real values were below 0.11× 10-6, 1.8 ×10 -9, 0.15 ×10-9and 0.5×10-9 for CO2, CH4, N2O and CO respectively, meeting the requirements for the atmospheric real-time measurements. During 6 days in-situ measurements of greenhouse gas outside the lab, the precision of target gas can reach 0. 05 ×10-6, 0.2 × 10-9, 0. 07 × 10-9, 0. 5 ×10-9 for CO2, CH4, N2O, CO, and inaccuracy can be 0.09 × 10-6, 0. 4× 10-9, 0. 14 × 10-9, 0. 5 × 10-9,respectively.

关 键 词：FTIR 温室气体及相关微量成分 标气模块 自动进样模块 在线观测 

分 类 号：X51[环境科学与工程—环境工程]