Knowledge Bank

The $14-15\mu m$ region is of particular importance in the remote sensing of atmospheric temperatures. The $10\circ 0-0110$ transition of $CO2$ has therefore been investigated in order to determine accurate values of the line intensities and half-widths in the Q-branch. A double beam TDL mounting was used. Slow scans of the spectra were performed, allowing the simultaneous recording of the line profile along with the fringes of Ge etalon. All measurements were carried out at room temperature for pressures ranging from 5 to 20 Torr in order to avoid excessive overlapping of lines. Eighteen lines were analyzed from Q(6) to Q(48). The transition moment is found to be equal to 0.1184 D. The obtained line widths exhibit a systematic departure of $10-1510-3cm-1atm-1$ as compared to the averaged values currently observed so far in a great number of $CO2$ parallel bands. This might explain some discrepancies in the retrieval of atmospheric temperatures from satellite observations.