References of "Rinsland, C. P"
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See detailObserved and simulated time evolution of HCl, ClONO2, and HF total column abundances
Kohlhepp, R; Ruhnke, R; Chipperfield, M P et al

in Atmospheric Chemistry and Physics (2012), 12(7), 3527--3556

Time series of total column abundances of hydrogen chloride (HCl), chlorine nitrate (ClONO2), and hydrogen fluoride (HF) were determined from ground-based Fourier transform infrared (FTIR) spectra ... [more ▼]

Time series of total column abundances of hydrogen chloride (HCl), chlorine nitrate (ClONO2), and hydrogen fluoride (HF) were determined from ground-based Fourier transform infrared (FTIR) spectra recorded at 17 sites belonging to the Network for the Detection of Atmospheric Composition Change (NDACC) and located between 80.05°N and 77.82°S. By providing such a near-global overview on ground-based measurements of the two major stratospheric chlorine reservoir species, HCl and ClONO2, the present study is able to confirm the decrease of the atmospheric inorganic chlorine abundance during the last few years. This decrease is expected following the 1987 Montreal Protocol and its amendments and adjustments, where restrictions and a subsequent phase-out of the prominent anthropogenic chlorine source gases (solvents, chlorofluorocarbons) were agreed upon to enable a stabilisation and recovery of the stratospheric ozone layer. The atmospheric fluorine content is expected to be influenced by the Montreal Protocol, too, because most of the banned anthropogenic gases also represent important fluorine sources. But many of the substitutes to the banned gases also contain fluorine so that the HF total column abundance is expected to have continued to increase during the last few years. The measurements are compared with calculations from five different models: the two-dimensional Bremen model, the two chemistry-transport models KASIMA and SLIMCAT, and the two chemistry-climate models EMAC and SOCOL. Thereby, the ability of the models to reproduce the absolute total column amounts, the seasonal cycles, and the temporal evolution found in the FTIR measurements is investigated and inter-compared. This is especially interesting because the models have different architectures. The overall agreement between the measurements and models for the total column abundances and the seasonal cycles is good. Linear trends of HCl, ClONO2, and HF are calculated from both measurement and model time series data, with a focus on the time range 2000–2009. This period is chosen because from most of the measurement sites taking part in this study, data are available during these years. The precision of the trends is estimated with the bootstrap resampling method. The sensitivity of the trend results with respect to the fitting function, the time of year chosen and time series length is investigated, as well as a bias due to the irregular sampling of the measurements. The measurements and model results investigated here agree qualitatively on a decrease of the chlorine species by around 1%yr-1. The models simulate an increase of HF of around 1%yr-1. This also agrees well with most of the measurements, but some of the FTIR series in the Northern Hemisphere show a stabilisation or even a decrease in the last few years. In general, for all three gases, the measured trends vary more strongly with latitude and hemisphere than the modelled trends. Relative to the FTIR measurements, the models tend to underestimate the decreasing chlorine trends and to overestimate the fluorine increase in the Northern Hemisphere. At most sites, the models simulate a stronger decrease of ClONO2 than of HCl. In the FTIR measurements, this difference between the trends of HCl and ClONO2 depends strongly on latitude, especially in the Northern Hemisphere. [less ▲]

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See detailDecrease of the Carbon Tetrachloride (CCl4) Loading above Jungfraujoch, based on High Resolution Infrared Solar Spectra recorded between 1999 and 2011
Rinsland, C. P.; Mahieu, Emmanuel ULg; Demoulin, Philippe ULg et al

in Journal of Quantitative Spectroscopy & Radiative Transfer (2012), 113

The long-term trend of the atmospheric carbon tetrachloride (CCl4) burden has been retrieved from high spectral resolution infrared solar absorption spectra recorded between January 1999 and June 2011 ... [more ▼]

The long-term trend of the atmospheric carbon tetrachloride (CCl4) burden has been retrieved from high spectral resolution infrared solar absorption spectra recorded between January 1999 and June 2011. The observations were made with a Fourier transform spectrometer at the northern mid-latitude, high altitude Jungfraujoch station in Switzerland (46.5°N latitude, 8.0°E longitude, 3580 m altitude). Total columns were derived from spectrometric analysis of the strong CCl4 ν3 band at 794 cm-1, accounting for all interfering molecules (e.g., H2O, CO2, O3, and a dozen weakly absorbing gases). A significant improvement in the fitting residuals and in the retrieved CCl4 columns was obtained by taking into account line mixing in a strong interfering CO2 Q branch. This procedure had never been implemented in remote sensing CCl4 retrievals though its importance was noted in earlier studies. A fit to the CCl4 daily mean total column time series returns a statistically-significant long-term trend of (-1.49±0.08 x 1013 molec./cm2)/yr, 2-σ. This corresponds to an annual decrease of (-1.31±0.07) pptv for the mean free tropospheric volume mixing ratio. Furthermore, the total column data set reveals a weak seasonal cycle with a peak-to-peak amplitude of 4.5 %, with minimum and maximum values occurring in mid-February and mid-September, respectively. This small seasonal modulation is attributed primarily to the residual influence of tropopause height changes throughout the year. The negative trend of the CCl4 loading reflects the continued impact of the regulations implemented by the Montreal Protocol and its strengthening amendments and adjustments. Despite this statistically significant decrease, the CCl4 molecule currently remains an important contributor to the atmospheric chlorine budget, and thus deserves further monitoring, to ensure continued compliance with these strengthenings, globally. Our present findings are briefly discussed with respect to recent relevant CCl4 investigations at the ground and from space. [less ▲]

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See detailFormic acid above the Jungfraujoch during 1985–2007: observed variability, seasonality, but no long-term background evolution
Zander, Rodolphe ULg; Duchatelet, Pierre ULg; Mahieu, Emmanuel ULg et al

in Atmospheric Chemistry and Physics (2010), 10(20), 10047--10065

This paper reports on daytime total vertical column abundances of formic acid (HCOOH) above the Northern mid-latitude, high altitude Jungfraujoch station (Switzerland; 46.5° N, 8.0° E, 3580 m alt.). The ... [more ▼]

This paper reports on daytime total vertical column abundances of formic acid (HCOOH) above the Northern mid-latitude, high altitude Jungfraujoch station (Switzerland; 46.5° N, 8.0° E, 3580 m alt.). The columns were derived from the analysis of infrared solar observations regularly performed with high spectral resolution Fourier transform spectrometers during over 1500 days between September 1985 and September 2007. The investigation was based on the spectrometric fitting of five spectral intervals, one encompassing the HCOOH ν6 band Q branch at 1105 cm−1, and four additional ones allowing to optimally account for critical temperature-sensitive or time-evolving interferences by other atmospheric gases, in particular HDO, CCl2F2 and CHClF2. The main results derived from the 22 years long database indicate that the free tropospheric burden of HCOOH above the Jungfraujoch undergoes important short-term daytime variability, diurnal and seasonal modulations, inter-annual anomalies, but no significant long-term background change. A major progress in the remote determination of the atmospheric HCOOH columns reported here has resulted from the adoption of new, improved absolute spectral line intensities for the infrared ν6 band of trans-formic acid, resulting in retrieved free tropospheric loadings being about a factor two smaller than if derived with previous spectroscopic parameters. Implications of this significant change with regard to earlier remote measurements of atmospheric formic acid and comparison with relevant Northern mid-latitude findings, both in situ and remote, will be assessed critically. Sparse HCOOH model predictions will also be evoked and assessed with respect to findings reported here. [less ▲]

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See detailValidation of five years (2003–2007) of SCIAMACHY CO total column measurements using ground-based spectrometer observations
de Laat, A. T. J.; Gloudemans, A. M. S.; Schrijver, H. et al

in Atmospheric Measurement Techniques (2010), 3(5), 1457--1471

This paper presents a validation study of SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) carbon monoxide (CO) total column measurements from the Iterative Maximum ... [more ▼]

This paper presents a validation study of SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) carbon monoxide (CO) total column measurements from the Iterative Maximum Likelihood Method (IMLM) algorithm using ground-based spectrometer observations from twenty surface stations for the five year time period of 2003–2007. Overall we find a good agreement between SCIAMACHY and ground-based observations for both mean values as well as seasonal variations. For high-latitude Northern Hemisphere stations absolute differences between SCIAMACHY and ground-based measurements are close to or fall within the SCIAMACHY CO 2σ precision of 0.2 × 1018 molecules/cm2 (~10%) indicating that SCIAMACHY can observe CO accurately at high Northern Hemisphere latitudes. For Northern Hemisphere mid-latitude stations the validation is complicated due to the vicinity of emission sources for almost all stations, leading to higher ground-based measurements compared to SCIAMACHY CO within its typical sampling area of 8° × 8°. Comparisons with Northern Hemisphere mountain stations are hampered by elevation effects. After accounting for these effects, the validation provides satisfactory results. At Southern Hemisphere mid- to high latitudes SCIAMACHY is systematically lower than the ground-based measurements for 2003 and 2004, but for 2005 and later years the differences between SCIAMACHY and ground-based measurements fall within the SCIAMACHY precision. The 2003–2004 bias is consistent with previously reported results although its origin remains under investigation. No other systematic spatial or temporal biases could be identified based on the validation presented in this paper. Validation results are robust with regard to the choices of the instrument-noise error filter, sampling area, and time averaging required for the validation of SCIAMACHY CO total column measurements. Finally, our results show that the spatial coverage of the ground-based measurements available for the validation of the 2003–2007 SCIAMACHY CO columns is sub-optimal for validation purposes, and that the recent and ongoing expansion of the ground-based network by carefully selecting new locations may be very beneficial for SCIAMACHY CO and other satellite trace gas measurements validation efforts. [less ▲]

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See detailAn empirical line-by-line model for the infrared solar transmittance spectrum from 700 to 5000 cm(-1)
Hase, F.; Demoulin, Philippe ULg; Sauval, A. J. et al

in Journal of Quantitative Spectroscopy & Radiative Transfer (2006), 102(3), 450-463

An empirical line-by-line model for the infrared solar transmittance spectrum is presented. The model can be incorporated into radiative transfer codes to allow fast calculation of all relevant emission ... [more ▼]

An empirical line-by-line model for the infrared solar transmittance spectrum is presented. The model can be incorporated into radiative transfer codes to allow fast calculation of all relevant emission and absorption features in the solar spectrum in the mid-infrared region from 700 to 5000 cm(-1). The transmittance is modelled as a function of the diameter of the field-of-view centered on the solar disk: the line broadening due to solar rotation as well as center-to-limb variations in strength and width are taken into account for stronger lines. Applications of the model presented here are in the fields of terrestrial remote sensing in the mid-infrared spectral region when the sun is used as radiation source or scattered solar radiation contributes to the measured signal and in the fields of atmospheric radiative transfer algorithms which compute the propagation of infrared solar radiation in the terrestrial atmosphere. (c) 2006 Elsevier Ltd. All rights reserved. [less ▲]

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See detailATMOS/ATLAS 3 infrared profile measurements of clouds in the tropical and subtropical upper troposphere
Rinsland, C. P.; Gunson, M. R.; Wang, P.-H. et al

in Journal of Quantitative Spectroscopy & Radiative Transfer (1998), 60(5), 903-919

Vertical profiles of infrared cirrus extinction have been derived from tropical and subtropical upper tropospheric solar occultation spectra. The measurements were recorded by the Atmospheric Trace ... [more ▼]

Vertical profiles of infrared cirrus extinction have been derived from tropical and subtropical upper tropospheric solar occultation spectra. The measurements were recorded by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer during the Atmospheric Laboratory for Applications and Sciences (ATLAS) 3 shuttle flight in November 1994. The presence of large numbers of small ice crystals is inferred from the appearance of broad extinction features in the 8-12 mu m region. These features were observed near the tropopause and at lower altitudes. Vertical profiles of the ice extinction (km(-1)) in microwindows at 831, 957, and 1204 cm(-1) have been retrieved from the spectra and analyzed with a model for randomly oriented spheroidal ice crystals. An area-equivalent spherical radius of 6 mu m is estimated from the smallest ice crystals observed in the 8-12 mu m region. Direct penetration of clouds into the lower stratosphere is inferred from observations of cloud extinction extending from the upper troposphere to 50 mbar (20 km altitude). Cloud extinction between 3 and 5 mu m shows very little wavelength dependence, at least for the cases observed by the ATMOS instrument in the tropics and subtropics during ATLAS 3. Published by Elsevier Science Ltd. [less ▲]

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See detailATMOS/ATLAS 3 infrared profile measurements of trace gases in the November 1994 tropical and subtropical upper troposphere
Rinsland, C. P.; Gunson, M. R.; Wang, P.-H. et al

in Journal of Quantitative Spectroscopy & Radiative Transfer (1998), 60(5), 891-901

Vertical mixing ratio profiles of four relatively long-lives gases, HCN, C2H2, CO, and C2H6, have been retrieved from 0.01 cm(-1) resolution infrared solar occultation spectra recorded between latitudes ... [more ▼]

Vertical mixing ratio profiles of four relatively long-lives gases, HCN, C2H2, CO, and C2H6, have been retrieved from 0.01 cm(-1) resolution infrared solar occultation spectra recorded between latitudes of 5.3 degrees N and 31.4 degrees N. The observations were obtained by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer during the Atmospheric Laboratory for Applications and Science (ATLAS) 3 shuttle flight, 3-12 November 1994. Elevated mixing ratios below the tropopause were measured for these gases during several of the occultations. The positive correlations obtained between the simultaneously measured mixing ratios suggest that the enhancements are likely the result of surface emissions, most likely biomass burning and/or urban industrial activities, followed by common injection via deep convective transport of the gases to the upper troposphere. The elevated levels of HCN may account for at least part of the "missing NOy" in the upper troposphere. Comparisons of the observations with values measured during a recent aircraft campaign are presented. Published by Elsevier Science Ltd. [less ▲]

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See detailThe 1994 northern midlatitude budget of stratospheric chlorine derived from ATMOS/ATLAS-3 observations
Zander, Rodolphe ULg; Mahieu, Emmanuel ULg; Gunson, M. R. et al

in Geophysical Research Letters (1996), 23(17), 2357-2360

Volume mixing ratio (VMR) profiles of the chlorine-bearing gases HCl, ClONO2, CCl3F, CCl2F2, CHClF2, CCl4, and CH3Cl have been measured between 3 and 49 degrees northern- and 65 to 72 degrees southern ... [more ▼]

Volume mixing ratio (VMR) profiles of the chlorine-bearing gases HCl, ClONO2, CCl3F, CCl2F2, CHClF2, CCl4, and CH3Cl have been measured between 3 and 49 degrees northern- and 65 to 72 degrees southern latitudes with the Atmospheric Trace MOlecule Spectroscopy (ATMOS) instrument during the ATmospheric Laboratory for Applications and Science (ATLAS)-3 shuttle mission of 3 to 12 November 1994. A subset of these profiles obtained between 20 and 49 degrees N at sunset, combined with ClO profiles measured by the Millimeter-wave Atmospheric Sounder (MAS) also from aboard ATLAS-3, measurements by balloon for HOCl, CH3CCl3 and C2Cl3F3, and model calculations for COClF indicates that the mean burden of chlorine, Cl-TOT, was equal to (3.53 +/- 0.10) ppbv (parts per billion by volume), 1-sigma, throughout the stratosphere at the time of the ATLAS 3 mission. This is some 37% larger than the mean 2.58 ppbv value measured by ATMOS within the same latitude zone during the Spacelab 3 flight of 29 April to 6 May 1985, consitent with an exponential growth rate of the chlorine loading in the stratosphere equal to 3.3%/yr or a linear increase of 0.10 ppbv/yr over the Spring-1985 to Fall-1994 time period. These findings are in agreement with both the burden and increase of the main anthropogenic Cl-bearing source gases at the surface during the 1980s, confirming that the stratospheric chlorine loading is primarily of anthropogenic origin. [less ▲]

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See detailIncrease of stratospheric carbon tetrafluoride (CF4) based on ATMOS observations from space
Zander, Rodolphe ULg; Solomon, S.; Mahieu, Emmanuel ULg et al

in Geophysical Research Letters (1996), 23(17), 2353-2356

Stratospheric volume mixing ratio profiles of carbon tetrafluoride, CF4, obtained with the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument during the ATLAS (Atmospheric Laboratory for ... [more ▼]

Stratospheric volume mixing ratio profiles of carbon tetrafluoride, CF4, obtained with the Atmospheric Trace Molecule Spectroscopy (ATMOS) instrument during the ATLAS (Atmospheric Laboratory for Applications and Science) -3 mission of 1994 are reported. Overall the profiles are nearly constant over the altitude range 20 to 50 km, indicative of the very long lifetime of CF4 in the atmosphere. In comparison to the stratospheric values of CF4 inferred from the ATMOS/Spacelab 3 mission of 1985, the 1994 concentrations are consistent with an exponential increase of (1.6 +/- 0.6)%/yr. This increase is discussed with regard to previous results and likely sources of CF4 at the ground. Further, it is shown that simultaneous measurements of N2O and CF4 provide a means of constraining the lower limit of the atmospheric lifetime of CF4 at least 2,300 years, two sigma. [less ▲]

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See detailTrends of OCS, HCN, SF6, CHClF2, (HCFC-22) in the lower stratosphere from 1985 and 1994 atmospheric trace molecule spectroscopy experiment measurements near 30 degrees N latitude
Rinsland, C. P.; Mahieu, Emmanuel ULg; Zander, Rodolphe ULg et al

in Geophysical Research Letters (1996), 23(17), 2349-2352

Volume mixing ratio (VMR) profiles of OCS, HCN, SF6, and CHClF2 (HCFC-22) have been measured near 30 degrees N latitude by the Atmospheric Trace Molecule Spectroscopy Fourier transform spectrometer during ... [more ▼]

Volume mixing ratio (VMR) profiles of OCS, HCN, SF6, and CHClF2 (HCFC-22) have been measured near 30 degrees N latitude by the Atmospheric Trace Molecule Spectroscopy Fourier transform spectrometer during shuttle flights on 29 April-6 May 1985 and 3-2 November 1994. The change in the concentration of each molecule in the lower stratosphere has been derived for this 9 1/2-year period by comparing measurements between potential temperatures of 395 to 800 K (similar to 17 to 30 km altitude) relative to simultaneously measured values of the long-lived tracer N2O. Exponential rates of increase inferred for 1985-to-1994 from these comparisons are (0.1 +/- 0.4)% yr(-1) for OCS, (1.0 +/- 1.0)% yr(-1) for HCN, (8.0+/-0.7)% yr(-1) for SF6, and (8.0 +/- 1.0)% yr(-1) for CHClF2 (HCFC-22), 1 sigma. The lack of an appreciable trend for OCS suggests the background (i.e., nonvolcanic) source of stratospheric aerosol was the same during the two periods. These results are compared with trends reported in the literature. [less ▲]

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See detailThe Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment: Deployment on the ATLAS Space Shuttle missions
Gunson, Michael R.; Abbas, M. M.; Abrams, M. C. et al

in Geophysical Research Letters (1996), 23(17), 2333-2336

The ATMOS Fourier transform spectrometer was flown for a fourth time on the Space Shuttle as part of the ATLAS-3 instrument payload in November 1994. More than 190 sunrise and sunset occultation events ... [more ▼]

The ATMOS Fourier transform spectrometer was flown for a fourth time on the Space Shuttle as part of the ATLAS-3 instrument payload in November 1994. More than 190 sunrise and sunset occultation events provided measurements of more than 30 atmospheric trace gases at latitudes 3-49 degrees N and 65-72 degrees S, including observations both inside and outside the Antarctic polar vortex. The instrument configuration, data retrieval methodology, and mission background are described to place in context analyses of ATMOS data presented in this issue. [less ▲]

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See detailAPRIL 1993 ARCTIC PROFILES OF STRATOSPHERIC HCL, CLONO2, AND CCL2F2 FROM ATMOSPHERIC TRACE MOLECULE SPECTROSCOPY ATLAS 2 INFRARED SOLAR OCCULTATION SPECTRA
Rinsland, C. P.; Gunson, M. R.; Abrams, M. C. et al

in Journal of Geophysical Research (1995), 100(D7), 14019-14027

Partitioning among the major components of the stratospheric odd chlorine family inside and outside of the remanent Arctic vortex has been studied on the basis of infrared solar occultation measurements ... [more ▼]

Partitioning among the major components of the stratospheric odd chlorine family inside and outside of the remanent Arctic vortex has been studied on the basis of infrared solar occultation measurements obtained by the atmospheric trace molecule spectroscopy (ATMOS) Fourier transform spectrometer during the ATLAS 2 shuttle mission (April 8-17, 1993). Profiles of hydrogen chloride (HCl) and simultaneous profiles of chlorine nitrate (ClONO2) and CFC-12 (CCl2F2) are reported for examples of in-vortex and out-of-vortex conditions. Increased ClONO2 volume-mixing ratios (VMRs) are measured in the vortex below 20 mbar (similar to 25 km altitude) with a peak ClONO2 VMR of 2.05 +/- 0.45 ppbv (10(-9) per volume) at 56 mbar (similar to 19 km altitude). The reported error correspond to la uncertainties. Simultaneous CCl2F2 and N2O measurements, combined with published empirical relations, indicate that only 0.34 +/- 0.15 ppbv, about 10% of total chlorine, was bound in organic species at the ClONO2 VMR peak in the vortex. A colocated vortex profile of HCl, referenced to simultaneous N2O VMR measurements, has been used to derive a HCl mixing ratio of 1.21 +/- 0.12 ppbv corresponding to the ClONO2 VMR peak. The internal consistency of the ATMOS measurements is demonstrated by the agreement between the total chlorine mixing ratio of 3.60 +/- 0.72 ppbv derived at the ClONO2 VMR peak in the vortex and HCl measurements of 3.37 +/- 0.37 and 3.76 +/- 0.41 ppbv at 0.56 mbar, where HCl is the only significant chlorine-bearing molecule. Outside the vortex the mixing ratio of HCl exceeds the mixing ratio of ClONO2 throughout the stratosphere. [less ▲]

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See detailINCREASE IN LEVELS OF STRATOSPHERIC CHLORINE AND FLUORINE LOADING BETWEEN 1985 AND 1992
Gunson, M. R.; Abrams, M. C.; Lowes, L. L. et al

in Geophysical Research Letters (1994), 21(20), 2223-2226

Mixing ratios of 3.44 ppbv (parts per billion by volume) and 1.23 ppbv for HCl and HF above 50 km, surrogates for total chlorine and fluorine, have been measured by the Atmospheric Trace Molecule ... [more ▼]

Mixing ratios of 3.44 ppbv (parts per billion by volume) and 1.23 ppbv for HCl and HF above 50 km, surrogates for total chlorine and fluorine, have been measured by the Atmospheric Trace Molecule Spectroscopy (ATMOS) experiment on a March 1992 flight of the Space Shuttle. Compared to the measured values obtained on a 1985 flight, these correspond to a 37% and 62% increase for HCl and HF, respectively. The derived trend in HCl (similar to 0.13 ppbv per year) is in good agreement with the model-predicted increase in chlorine loading of 0.13 ppbv per year [Prather and Watson. 1990], and with the measured trends in HCl total column abundance from reported ground-based observations. The main source of this change can be attributed to the release of man-made chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs). This new value for HCl represents an upper limit to the inorganic chlorine concentration in the stratosphere available for participation in photochemical processes which destroy ozone. [less ▲]

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See detailATMOS ATLAS-1 MEASUREMENTS OF SULFUR-HEXAFLUORIDE (SF6) IN THE LOWER STRATOSPHERE AND UPPER TROPOSPHERE
Rinsland, C. P.; Gunson, M. R.; Abrams, M. C. et al

in Journal of Geophysical Research (1993), 98(D11), 20491-20494

Vertical profiles of sulfur hexafluoride (SF6) in the lower stratosphere and upper troposphere have been retrieved from 0.01-cm-1 resolution infrared solar occultation spectra recorded by the Atmospheric ... [more ▼]

Vertical profiles of sulfur hexafluoride (SF6) in the lower stratosphere and upper troposphere have been retrieved from 0.01-cm-1 resolution infrared solar occultation spectra recorded by the Atmospheric Trace Molecule Spectroscopy (ATMOS) Fourier transform spectrometer during the ATLAS (Atmospheric Laboratory for Applications and Science) 1 shuttle mission of March 24 to April 2, 1992. Based on measurements of the unresolved absorption by the SF6 nu3 band Q branch at 947.9 cm-1, average SF6 volume mixing ratios and 1-sigma uncertainties of 3.20 +/- 0.54 parts per trillion by volume (pptv; 10(-12) ppv) at 200 mbar (approximately 11.8 km) declining to 2.86 +/- 0.29 pptv at 100 mbar (approximately 16.2 km) and 1.95 +/- 0.50 pptv at 30 mbar (approximately 23.9 km) have been retrieved. The profiles show no obvious dependence with latitude over the range of the measurements (eight occultations spanning 28-degrees-S to 54-degrees-S). Assuming an exponential growth model and applying a correction for the interhemispheric concentration difference, an average SF6 rate of increase of 8.7 +/- 2.2% per year, 2 sigma, between 12 and 18 km has been derived by fitting the present measurements, ATMOS measurements from the April-May 1985 Spacelab 3 mission, and balloon-borne IR measurements obtained in March 1981 and June 1988. [less ▲]

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