基于可调谐半导体激光吸收光谱技术对开放式长光程大气CO_2的测量

Measurement of Open-Path Atmospheric CO_2 Based on Tunable Diode Laser Absorption Spectroscopy

CO_2是地球大气中第三大含量的痕量气体,对温室效应影响最大,主要来源于人类的日常活动,测量大气CO_2浓度对了解地区CO_2的周期性变化与气候变化的内在规律有重要意义。基于可调谐半导体激光吸收光谱(tunable diode laser absorption spectroscopy,TDLAS)技术,系统选择CO_2在2004 nm附近的吸收线,采用直接吸收光谱处理方法,对开放式长光程大气下的CO_2进行了连续测量。通过与手持CO_2测量仪的对比测量,二者的相关系数达到0.8371,二者的标准偏差为7.204 ppm,测量结果的变化趋势符合较好,证明了实验系统的可行性,为国内激光遥测CO_2提供了一种重要的思路与方法。

CO2 concentration has ranked the third of all the trace gas in the earth＇s atmosphere and exerts a tremendous influence on greenhouse effect. It mainly conies from human＇s daily activities. Detecting atmo- spheric CO2 concentration has important significance in understanding the periodic changes of CO2 and the inherent law of climate change. Based on tunable diode laser absorption spectroscopy （TDLAS） technology the absorption line of CO2 near 2004 nm was selected, the open-path atmospheric CO2 was continuously inea- sured by direct absorption processing method. Compared with a hand-held COs measurement instrument their correlation coefficient is 0.8371, and the standard deviation is 7.204 ppm. The results show good con- sistency between the TDLAS and hand-held COs measurement instrument, and the feasibility of experiment system is proved. It provides an important way and a method for the domestic remote sensing of COs with laser.