HR: 0800h
AN: A51C-0787    [Abstracts]
TI: Spectral line parameters for CO$_2$ bands near 4.8 $\mu$m
AU: * Tanaka, T
EM: tanaka.tomoaki@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Fukabori, M
EM: fukabori@mri-jma.go.jp
AF: Meteorological Research Institute, 1-1 Nagamine, Tsukuba, 305-0052 Japan
AU: Nakajima, H
EM: hide@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Yokota, T
EM: yoko@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AU: Watanabe, T
EM: Takeshi_Watanabe@TRC.toray.co.jp
AF: Toray Research Center Inc., 3-3-7 Otsu, Otsu, 520-8567 Japan
AU: Sasano, Y
EM: sasano@nies.go.jp
AF: National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506 Japan
AB: High-resolution spectra of CO$_2$ bands near 4.8 $\mu$m m region were obtained by using a Bruker IFS 120HR spectrometer. In this study, we measured the line strengths and half-widths of the (11101-00001), (11102-00001), (20001-01101), and (12201-01101) bands of CO$_2$. Two weak hot bands [the (20001-01101) and (12201-01101) bands] are overlapped with the strong (11101-00001) band, thus the spectrum of CO$_2$ near 4.8 $\mu$m showed a complicated feature. The spectra were measured with a resolution of 0.01 cm$^{-1}$ and in the wavelength region of 4.6 to 5.4 $\mu$m. Six different combinations of CO$_2$-N$_2$ and CO$_2$-O$_2$ mixtures with a total pressure of 380 torr were used for the measurements. The sample pressure was measured with an MKS Baratron pressure gauge with a 1000-torr head. Measurements were performed using a 658.4 cm-long cell with CaF$_2$ windows. The temperature of the sample gas was measured with a thermocouple and was kept at 299K during the measurement. A nonlinear least-squares fitting procedure is used to determine the line strengths and half-widths of the above bands. As a result of the analysis, the squares of the vibrational dipole moment and the coefficients of the Herman-Wallis factor for these bands are derived. Obtained values were compared with the values in the HITRAN database. The (11101-00001), (11102-00001), (20001-01101), and (12201-01101) bands of CO$_2$ reveal remarkable contrast in intensity perturbations, i.e. enhancing the P-branch intensity while reducing that of the R-branch. These strong perturbations are caused by a Coriolis interaction. We take into account this interaction by introducing the Coriolis interaction coefficients and the values of these coefficients for CO$_2$ bands are determined. Observed and calculated values of the Coriolis interaction coefficients are compared for these bands.
DE: 1640 Remote sensing
SC: Atmospheric Sciences [A]
MN: 2004 AGU Fall Meeting