Our changing atmosphere: evidence based on long-term infrared solar observations at the Jungfraujoch since 1950.

The Institute of Astrophysics of the University of Liège has been present at the High Altitude Research Station Jungfraujoch, Switzerland, since the late 1940s, to perform spectrometric solar observations under dry and weakly polluted high-mountain conditions. Several solar atlases of photometric quality, extending altogether from the near-ultra-violet to the middle-infrared, were produced between 1956 and 1994, first with grating spectrometers then with Fourier transform instruments. During the early 1970s, scientific concerns emerged about atmospheric composition changes likely to set in as a consequence of the growing usage of nitrogen-containing agricultural fertilisers and the industrial production of chlorine-bearing compounds such as the chlorofluorocarbons and hydro-chlorofluorocarbons.

Retrievals for the atmospheric chemistry experiment Fourier-transform spectrometer.

SCISAT-1, also known as the Atmospheric Chemistry Experiment, is a satellite mission for remote sensing of the Earth's atmosphere, launched on 12 August 2003. The primary instrument on the satellite is a 0.02 cm(-1) resolution Fourier-transform spectrometer operating in the mid-IR (750-4400 cm(-1)).

Enhanced upper tropical tropospheric COS: impact on the stratospheric aerosol layer.

Carbonyl sulfide (COS) is considered to be a major source of the stratospheric sulfate aerosol during periods of volcanic quiescence. We measured COS at the tropical tropopause and find mixing ratios to be 20 to 50% larger than are assumed in models. The enhanced COS levels are correlated with high concentrations of biomass-burning pollutants like carbon monoxide (CO) and hydrogen cyanide (HCN).

Atmospheric Trace Molecule Spectroscopy (ATMOS) Experiment Version 3 data retrievals.

Version 3 of the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment data set for some 30 trace and minor gas profiles is available. From the IR solar-absorption spectra measured during four Space Shuttle missions (in 1985, 1992, 1993, and 1994), profiles from more than 350 occultations were retrieved from the upper troposphere to the lower mesosphere. Previous results were unreliable for tropospheric retrievals, but with a new global-fitting algorithm profiles are reliably returned down to altitudes as low as 6.

The v(1)+v(3) Bands of the (16)O(17)O(16)O and (16)O(16)O(17)O Isotopomers of Ozone.

Using 0.002 cm(-1) resolution Fourier transform absorption spectra of an (17)O enriched ozone sample, an extensive analysis of the v(1)+v(3) bands of the (16)O(17)O(16)O and (16)O(16)O(17)O isotopomers of ozone has been performed for the first time. The experimental rotational levels of the (101) vibrational states were satisfactorily reproduced using a Hamiltonian matrix that takes into account the observed rovibrational resonances.

New High-Resolution Analysis of the 3nu(3) and 2nu(1) + nu(3) Bands of Nitrogen Dioxide (NO(2)) by Fourier Transform Spectroscopy.

Using new high-resolution Fourier transform spectra recorded at the University of Denver in the 2-µm region, a new and more extended analysis of the 2nu(1) + nu(3) and 3nu(3) bands of nitrogen dioxide, located at 4179.9374 and 4754.2039 cm(-1), respectively, has been performed.

Analysis of the nu8 + nu9 Band of HNO3, Line Positions and Intensities, and Resonances Involving the v6 = v7 = 1 Dark State.

Using a high-resolution (R = 0.0025 cm-1) Fourier transform spectrum of nitric acid recorded at room temperature in the 1100-1240 cm-1 region, it has been possible to perform a more extended analysis of the nu8 + nu9 band of HNO3 centered at 1205.7075 cm-1.

Temperature Dependence of Air-Broadening and Shift Coefficients of O3 Lines in the nu1 Band.

High-resolution Fourier transform absorption spectra of ozone broadened by dry air have been recorded at a number of temperatures from -63°C to 29°C. Using a multispectrum nonlinear least-squares procedure, we fit 29 of these spectra simultaneously to determine the air-broadening and shift coefficients and their temperature dependences for 450 lines in the 9-&mgr;m region; most of these belong to the nu1 band. Partial air-broadening results were obtained for 104 additional lines, and room-temperature self-broadening coefficients were also determined for most of the 554 lines measured.

Air-Broadening and Shift Coefficients of O3 Lines in the nu2 Band and Their Temperature Dependence.

Room temperature measurements of self- and air-broadening coefficients are reported for over 370 transitions covering a range of 0 View Article and Find Full Text PDF

1995 Atmospheric Trace Molecule Spectroscopy (ATMOS) linelist.

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.

Pressure sounding of the middle atmosphere from ATMOS solar occultation measurements of atmospheric CO(2) absorption lines.

A method for retrieving the atmospheric pressure corresponding to the tangent point of an infrared spectrum recorded in the solar occultation mode is described and applied to measurements made by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier-transform spectrometer. Tangent pressure values are inferred from measurements of isolated CO(2) lines with temperature-insensitive strengths by measuring the slant-column CO(2) amount and by adjusting the viewing geometry until the calculated column matches the observed column. Tangent pressures are determined with a spectroscopic precision of l%-3%, corresponding to a tangent-point height precision of 70-210 m.

Remote sensing of the Earth's atmosphere from space with high-resolution Fourier-transform spectroscopy: development and methodology of data processing for the Atmospheric Trace Molecule Spectroscopy experiment.

The methodology of spectroscopic remote sensing with high-resolution Fourier-transform spectra obtained from low Earth orbit by the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment is discussed. During the course of the Atmospheric Laboratory for Applications and Science (ATLAS) shuttle missions (1992-1994) a flexible, yet reproducible, retrieval strategy was developed that culminated in the near-real-time processing of telemetry data into vertical profiles of atmospheric composition during the ATLAS-3 mission. The development, evolution, robustness, and validation of the measurements are presented and assessed with a summary comparison of trace-gas observations within the Antarctic polar vortex in November 1994.

Observations of the infrared solar spectrum from space by the ATMOS experiment.

The final flight of the Atmospheric Trace Molecule Spectroscopy experiment as part of the Atmospheric Laboratory for Applications and Science (ATLAS-3) Space Shuttle mission in 1994 provided a new opportunity to measure broadband (625-4800 cm(-1), 2.1-16 µm) infrared solar spectra at anunapodized resolution of 0.01 cm(-1) from space.

Infrared spectroscopic measurements of tropospheric trace gases.

Absorption features of several trace gases have been detected in 0.017-cm -(1)-resolution infrared spectra recorded over surface-level paths of 0.5 and 1.

Infrared measurements of HF and HCl total column abundances above Kitt Peak, 1977-1990: seasonal cycles, long-term increases, and comparisons with model calculations.

Series of high-resolution (approximately 0.01 cm-1) solar absorption spectra recorded with the McMath Fourier transform spectrometer on Kitt Peak (altitude 2.09 km, 31.

Measurements of Lorentz air-broadening coefficients and relative intensities in the H(2)(16)O pure rotational and v(2) bands from long horizontal path atmospheric spectra.

Lorentz air-broadening coefficients and relative intensities have been measured for forty-three lines in the pure rotational band and twenty lines in the v(2) band of H(2)(16)O between 800 and 1150 cm(-1). The results were derived from analysis of nine 0.017-cm(-1) resolution atmospheric absorption spectra recorded over horizontal paths of 0.

ATMOS data processing and science analysis methods.

The ATMOS (atmospheric trace molecule spectroscopy) instrument, a high speed Fourier transform spectrometer operating in the middle IR (2.2-16 microm), recorded more than 1500 solar spectra at approximately 0.0105-cm(-1) resolution during its first mission onboard the shuttle Challenger in the spring of 1985.

Measurements of air-, N(2)-, and O(2) -broadened halfwidths and pressure-induced line shifts in the v(3) band of (13)CH(4).

Air-, nitrogen-, and oxygen-broadened halfwidth and pressure-induced line shift coefficients have been measured for over seventy-five individual vibration-rotation transitions in the v(3) fundamental band of (13)CH(4)at 3 mum from room temperature IR laboratory absorption spectra recorded at a 0.01-cm(-1) resolution with a Fourier transform spectrometer. Transitions up to J" = 13 in the P-branch and J" = 7 in the R-branch were analyzed using a nonlinear least-squares curve fitting technique assuming a Voigt line shape.

Improved line parameters for ozone bands in the 10-microm spectral region.

A complete update of spectroscopic line parameters for the 10-microm bands of ozone is reported. The listing contains calculated positions, intensities, lower state energies, and air- and self-broadened halfwidths of more than 53,000 lines. The results have been generated using improved spectroscopic parameters obtained in a number of recent high resolution laboratory studies.

Spectroscopic line parameters for the nu(6) band of carbonyl fluoride.

New measurements and analysis of high resolution(0.0025 cm(-1)) laboratory spectra of the carbonyl fluoride v6 band are described. The data are used to generate line parameters suitable for high resolution atmospheric studies.

Measurements of argon broadened Lorentz width and pressureinduced line shift coefficients in the nu(4) band of (12)CH(4).

Room temperature argon broadened halfwidth and pressure-induced line shift coefficients have been determined for 118 transitions in the nu(4) band of (12)CH(4) from analysis of high resolution laboratory absorption spectra recorded with the McMath Fourier transform spectrometer operated on Kitt Peak by the National Solar Observatory. Transitions up to J''= 12 have been measured using a nonlinear least-squares spectral fitting procedure. The variation of the measured halfwidth coefficients with symmetry type and rotational quantum number is very similar to that measured previously for N(2) and air broadening, but the absolute values of the argon broadening coefficients are all smaller.

Line mixing effects in solar occultation spectra of the lower stratosphere: measurements and comparisons with calculations for the 1932-cm(-1) CO(2) Q branch.

Line mixing effects have been observed in a CO(2)Q branch recorded in 0.01-cm(-1) resolution IR solar occultation spectra of the lower stratosphere. The spectral data were obtained by the Atmospheric Trace Molecule Spectroscopy Fourier transform spectrometer during the Spacelab 3 shuttle mission in the spring of 1985.

Air-broadened Lorentz halfwidths and pressure-induced line shifts in the nu(4) band of (13)CH(4).

Air-broadened halfwidths and pressure-induced line shifts in the nu(4) fundamental of (13)CH(4) were determined from spectra recorded at room temperature and at 0.01-cm(-1) resolution using a Fourier transform spectrometer. Halfwidths and pressure shifts were determined for over 180 transitions belonging to J''values of View Article and Find Full Text PDF

Absolute intensities of CO(2) lines in the 3140-3410-cm(-1) spectral region.

Absolute intensities for 430 transitions belonging to eleven rotation-vibration bands of (12)C(16)O(2),(13)C(16)O(2) and(16)O(12)C(18)O in the 3140-3410-cm(-1) spectral region have been determined by analyzing spectra recorded at 0.01-cm(-1) resolution with the Fourier transform spectrometer in the McMath solar telescope complex at the National Solar Observatory on Kitt Peak. The data were recorded at room temperature and low pressures (<10 Torr) using a natural sample of carbon dioxide.