Pressure-broadening and narrowing coefficients and temperature dependence measurements of CO2 at 2.68 μm by laser diode absorption spectroscopy for atmospheric applications

By using a tunable diode laser absorption spectrometer in conjunction with a cryogenically cooled multipath cell, we have revisited the air-induced pressure-broadening coefficients and the narrowing coefficients related to the Dicke effect, as well as the temperature dependences, for the R(18) and R(20) lines of the (1 0° 1)I ← (0 0° 0) vibrational band at 2.68 μm of carbon dioxide. The selected transitions are used to probe in situ CO2 in the troposphere and the lower stratosphere by using balloon-borne laser sensors. The achieved measurements are thoroughly compared to existing former determinations. The impact of processing the in situ atmospheric CO2 spectra with this new set of molecular data is reported.

Figure optionsDownload as PowerPoint slideHighlights
► Determinate accurate spectroscopic parameters in order to process CO2 balloon spectra.
► Temperature dependence of air-broadening and air-narrowing coefficients.
► Application to CO2 atmospheric spectra.