RESUMEN
The Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment uses a Fourier-transform spectrometer on board the Space Shuttle to record infrared solar occultation spectra of the atmosphere at 0.01-cm(-1) resolution. The current version of the molecular spectroscopic database used for the analysis of the data obtained during three Space Shuttle missions between 1992 and 1994 is described. It is an extension of the effort first described by Brown et al. [Appl. Opt. 26, 5154 (1987)] to maintain an up-to-date database for the ATMOS experiment. The three-part ATMOS compilation contains line parameters of 49 molecular species between 0 and 10000 cm(-1). The main list, with nearly 700,000 entries, is an updated version of the HITRAN 1992 database. The second compilation contains supplemental line parameters, and the third set consists of absorption cross sections to represent the unresolvable features of heavy molecules. The differences between the ATMOS database and other public compilations are discussed.
RESUMEN
High-resolution spectra of H(2)(16)O vapor covering the region from 5750 to 7965 cm(-1) were used to determine experimental values of line positions and strengths of over 3750 vibration-rotation transitions in the (110)-(000), (011)-(000), (040)-(000), (120)-(000), (021)-(000), (200)-(000), (101)-(000), (002)-(000), (031)-(010), (210)-(010) and (111)-(010) bands from which rotational energy levels in the (040), (120), (021), (200), (101) and (002) vibrational states were obtained. The line strengths and frequencies reported here are considered to be a marked improvement over the values listed in the 1986 edition of the HITRAN database, and a preliminarly listing from this work has been included in the 1993 HITRAN edition.
RESUMEN
High-resolution spectra of O(17)- and O(18)-enriched water-vapor samples have been recorded with a Fourier transform spectrometer covering the region between 6600 and 7640 cmcm(-1). Experimental values of line positions and strengths of 1807 absorptions in the (120)-(000), (021)-(000), (200)-(000), (101)-(000), (002)-(000), bands of the two isotopic species were derived from the spectra. The analysis included the determination of accurate rotational levels belonging to the (120), (021), (200), (101), and (002) vibrational states of H(2)(17)O and H(2)(18)O.
RESUMEN
Self-broadened linewidths and pressure-induced frequency shifts of N(2)O were measured from spectra obtained at high spectral resolution in the 1800-2630 cm(-1) region. From measurements of 136 lines, the average pressure-shift coefficient was found to be -0.0015 ± 0.0006 cm(-1)/atm. The shift coefficients were found to have a weak J dependence, in which the magnitude of the coefficients increases with increasing values of J. Line-strength measurements were derived from spectra obtained at low sample pressures, and these data were analyzed to determine vibrational band strengths, rotationless dipole-moment matrix elements, and F factor coefficients for several bands in the 900-3600 cm(-1) region. Measurements of over 15,000 selected vibration-rotation transitions, including eight N(2)O isotopic species, were used in the various analyses.
RESUMEN
The N(2)O infrared spectrum from 900 to 4700 cm(-1) has been studied with a high-resolution Fourier-transform spectrometer. Measurements were made of line frequencies of several N(2)O isotopes for several ground-state and hot bands. A few of these bands are being reported for the first time, to my knowledge: the 1530-0330, 2330-0330, 0441-0440, 0441-0330, 0531-0330, and 1331-0330 bands of (14)N(2)(16)O. Also for the first time to my knowledge, perturbation-enhanced transitions in the 0710-0110 and 0730-0110 bands were assigned and measured. The frequencies have been analyzed to obtain a unique set of effective vibration-rotation parameters for each vibrational state. The results obtained from this research are of high accuracy for the ground-state and the first-excited-state bands of (14)N(2)(16)O, in which the computed frequencies derived from the least-squares fits are known to an absolute uncertainty of only +/-4 x 10(-5) for nonperturbed transitions.
RESUMEN
A description and summary of the latest edition of the AFGL HITRAN molecular absorption parameters database are presented. This new database combines the information for the seven principal atmospheric absorbers and twenty-one additional molecular species previously contained on the AFGL atmospheric absorption line parameter compilation and on the trace gas compilation. In addition to updating the parameters on earlier editions of the compilation, new parameters have been added to this edition such as the self-broadened halfwidth, the temperature dependence of the air-broadened halfwidth, and the transition probability. The database contains 348043 entries between 0 and 17,900 cm(-1). A FORTRAN program is now furnished to allow rapid access to the molecular transitions and for the creation of customized output. A separate file of molecular cross sections of eleven heavy molecular species, applicable for qualitative simulation of transmission and emission in the atmosphere, has also been provided.
RESUMEN
A nonlinear least-squares fitting procedure has been used to derive absolute intensities for lines in the P, R, and Q branches of the (11(1)0)II <-- 00(0)0 band of 12Cl602 (band center = 1932 cm(-1)) from long-path 0.01-cm(-1) resolution laboratory spectra. The spectral data were recorded at room temperature and low pressure (<10 Torr) with the Fourier transform spectrometer in the McMath solar telescope complex at Kitt Peak National Observatory. The observed line intensities were analyzed to derive the vibrational band intensity and F-factor coefficients. To obtain a good fit to the data, it was necessary to include terms in the expression for the F factor, which account for Coriolis-type and Fermi-type interactions and centrifugal distortion effects.
RESUMEN
The latest edition of the AFGL atmospheric absorption line parameters compilation for the seven most active infrared terrestrial absorbers is described. Major modifications to the atlas for this edition include updating of water-vapor parameters from 0 to 4300 cm(-1), improvements to line positions for carbon dioxide, substantial modifications to the ozone bands in the middle to far infrared, and improvements to the 7- and 2.3-microm bands of methane. The atlas now contains approximately 181,000 rotation and vibration-rotation transitions between 0 and 17,900 cm(-1). The sources of the absorption parameters are summarized.
RESUMEN
The vibration-rotation spectrum of HDO in the 2400-3300-cm(-1) region has been studied at 0.01-cm(-1) resolution with a Fourier transform spectrometer. Values of the ground state levels and levels in the (100) and (020) states have been determined from the data. The ground state levels are fitted to a Watson-type Ham-iltonian from which 17 rotational constants are obtained. Measurements of the strengths of over 1100 lines have been made using a nonlinear least-squares fitting technique, and 548 of these lines are analyzed to determine the band strengths, the coefficients of the F factors, and the Coriolis interaction parameters. The strengths of the A- and B-type (100) bands and the A- and B-type (020) bands are 53.2 +/- 0.9, 0.43 0.07, 6.00 +/- 0.54, and 2.75 +/-0.12 cm(-2) atm(-1) at 296 K, respectively.
RESUMEN
New line parameters of the methane spectrum have been incorporated in the AFGL compilation for the 2385-3200-cm(-1) region and were determined from data recorded at 0.01- and 0.02-cm(-1) resolution. Observed line positions and strengths are given for approximately 8076 absorptions with strengths >3.3 x 10(-24) cm/molecule (8.2 x 10(-5) cm(-2) atm(-1)). Lower state energies are given for 97% of the absorptions listed. Most of the lower states are determined through assignment of seven bands of (12)CH(4) (nu(1), nu(3), 2nu(2), nu(2) + nu(4), 2nu(4), nu(3) + nu(4) - nu(4) and nu(2) + nu(3) - nu(2)), four bands of (13)CH(4) (nu(3), 2nu(4), nu(2) + nu(4) and nu(3) + nu(4) - nu(4)), and three bands of CH(3)D (nu(1), nu(4), and 2nu(5)). A few of the lower state energies are determined experimentally from the data taken at cold sample temperatures.
RESUMEN
A new method is described for obtaining the temperature profile in the stratosphere and lower mesosphere from observations of the absorption spectrum of the high J lines of carbon dioxide at 4.3 microm. This concept is based upon the measurement of the integrated absorption of individual CO(2) lines whose strengths depend strongly on temperature and that the absorption of these lines are obtained from measurements of the solar or stellar spectrum through an atmospheric path. The technique involves a rapidly converging iterative process in which the equivalent widths of the individual vibration-rotation lines of CO(2) are used. Theoretical calculations are presented for balloon and satellite observations using a model atmosphere. Experimental results are given from spectra obtained with a balloon-borne Fourier interferometer spectrometer in which the sun was observed at low zenith angles. The experimental results are compared to rocketsonde data.