title: [Study of remote sensing the flux of carbon dioxide gas with tunable diode laser absorption spectroscopy].
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 microm 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 x m(-2) x 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, breaking 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.
authors: Key Lab of Environment Optics & Technology, and Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031, China. sxuemei@mail.ustc.edu.cn
authors: Xue-mei
authors: XM
authors: Song
authors: Jian-guo
authors: JG
authors: Liu
authors: Yu-jun
authors: YJ
authors: Zhang
authors: Yi-huai
authors: YH
authors: Lu
authors: Zong-yong
authors: ZY
authors: Zeng
authors: Ying
authors: Y
authors: He
authors: Yi-ben
authors: YB
authors: Cui
authors: Yong-zhi
authors: YZ
authors: Tian
authors: Lin
authors: L
authors: Tian