Simultaneous detection of atmospheric CO2 and H2O using a DFB diode laser based absorption spectrometer

In this paper, a high-resolution absorption spectrometer based on a continuous wave (CW) distributed feedback (DFB) diode laser near 2682.8 nm spectral region is developed, which is suitable for high sensitive detection of trace CO2 and H2O simultaneously. Spectral parameters (line strengths, air- and self-broadening coefficients) for CO2 absorption line at 3727.08279 cm-1 and H2O absorption line at 3727.73765 cm-1 are experimentally investigated, and a good agreement was obtained by comparing with the HITRAN database. H2O induced CO2 broadening coefficient is especially measured to upgrade the spectral signal processing algorithm model for field application. Finally, the developed diode laser absorption spectrometer was continuously deployed at AECORSQ Observatory onMt. Qomolangma, China, for approximate two days, which demonstrated the high sensitivity and stability of the sensor system for continuously atmospheric CO2 and H2O background observation.