光谱学与光谱分析, 2011, 31 (3): 803, 网络出版: 2011-08-16
可调谐半导体激光吸收光谱遥测二氧化碳通量的研究
Study of Remote Sensing the Flux of Carbon Dioxide Gas with Tunable Diode Laser Absorption Spectroscopy
可调谐半导体激光吸收光谱 二氧化碳浓度 二氧化碳通量 Tunable diode laser absorption spectroscopy Carbon dioxide concentration Flux of the carbon dioxide gas
摘要
可调谐半导体激光吸收光谱技术(TDLAS)具有高分辨率、 高灵敏度以及响应时间快等优点。 以室温下工作的近红外可调谐半导体激光器为光源, 通过波长调制方法对1 578 nm附近CO2气体吸收线的二次谐波信号测量, 结合双开放光路技术, 实现对不同高度层面700多米长光程范围内CO2气体浓度的快速在线检测。 结合大口径闪烁仪测量的莫宁-奥布霍夫长度和特征速度, 通过经验公式计算得到CO2气体的通量在-60~60 mg·m-2·s-1范围内波动。 实验数据与涡动相关比较表明, 两者数据整体变化趋势一致, 该方法可以获得较理想的结果。 突破了目前对近地面痕量气体通量的监测只能提供局地结果的现象, 使大面积范围内痕量气体通量的测量成为可能。
Abstract
Tunable diode laser absorption spectroscopy (TDLAS) technique is a new method to detect trace gas qualitatively or quantificationally based on the scan characteristic of the diode laser to obtain the absorption spectra in the characteristic absorption region. TDLAS is a highly sensitive, highly selective and fast time response trace gas detection technique. In the present paper, a DFB laser at room temperature was used as the light source, wavelength modulation method was employed, and the second harmonic signal of one absorption line near 1.578 μm of carbon dioxide molecule was measured. A system was built for online monitoring of carbon dioxide concentration within the optical path of more than 700 meters at different heights. Combined with Alonzo Mourning-Obukhov length and characteristic velocity detected by large aperture scintillometer, the flux of carbon dioxide gas calculated by the experiential formula is within -60~60 mg·m-2·s-1. The comparison of the datea detected by TDLAS system and the eddy covariance showed that the change of the data detected by TDLAS had a similar trend to that detected by the eddy covariance, and the best results can be produced by this method, breakking through the phenomenon of only providing the flux of trace gases near the ground at present, and making the measurement of trace gas fluxes within a large area possible.
宋雪梅, 刘建国, 张玉钧, 陆亦怀, 曾宗泳, 何莹, 崔益本, 田勇志, 田林. 可调谐半导体激光吸收光谱遥测二氧化碳通量的研究[J]. 光谱学与光谱分析, 2011, 31(3): 803. SONG Xue-mei, LIU Jian-guo, ZHANG Yu-jun, LU Yi-huai, ZENG Zong-yong, HE Ying, CUI Yi-ben, TIAN Yong-zhi, TIAN Lin. Study of Remote Sensing the Flux of Carbon Dioxide Gas with Tunable Diode Laser Absorption Spectroscopy[J]. Spectroscopy and Spectral Analysis, 2011, 31(3): 803.