Research on atmospheric CO2 remote sensing with open-path tunable diode laser absorption spectroscopy and comparison methods

An open-path atmospheric CO2CO2 measurement system was built based on tunable diode laser absorption spectroscopy (TDLAS). The CO2CO2 absorption line near 2μm2  μm was selected, measuring the atmospheric CO2CO2 with direct absorption spectroscopy and carrying on the comparative experiment with multipoint measuring instruments of the open-path. The detection limit of the TDLAS system is 1.94×10−61.94×10−6. The calibration experiment of three AZ-7752 handheld CO2CO2 measuring instruments was carried out with the Los Gatos Research gas analyzer. The consistency of the results was good, and the handheld instrument could be used in the TDLAS system after numerical calibration. With the contrast of three AZ-7752 and their averages, the correlation coefficients are 0.8828, 0.9004, 0.9079, and 0.9393 respectively, which shows that the open-path TDLAS has the best correlation with the average of three AZ-7752 and measures the concentration of atmospheric CO2CO2 accurately. Multipoint measurement provides a convenient comparative method for open-path TDLAS.