Stratospheric N2O5, CH4, and N2O profiles from IR solar occultation spectra
ABSTRACT Stratospheric volume mixing ratio profiles of N2O5, CH4, and N2O have been retrieved from a set of 0.052 cm–1 resolution (FWHM) solar occultation spectra recorded at sunrise during a balloon flight from Aire sur l'Adour, France (44 N latitude) on 12 October 1990. The N2O5 results have been derived from measurements of the integrated absorption by the 1246 cm–1 band. Assuming a total intensity of 4.3210–17 cm–1/molecule cm–2 independent of temperature, the retrieved N2O5 volume mixing ratios in ppbv (parts per billion by volume, 10–9), interpolated to 2 km height spacings, are 1.640.49 at 37.5 km, 1.920.56 at 35.5 km, 2.060.47 at 33.5 km, 1.950.42 at 31.5 km, 1.600.33 at 29.5 km, 1.260.28 at 27.5 km, and 0.850.20 at 25.5 km. Error bars indicate the estimated 1- uncertainty including the error in the total band intensity (20% has been assumed). The retrieved profiles are compared with previous measurements and photochemical model results.
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ABSTRACT: In the Arctic winter 1998/99, two balloon payloads were launched in a co-ordinated study of stratospheric bromine. Vertical profiles (9-28 km) of all known major organic Br species (CH3Br, C2H5Br, CH2BrCl, CHBrCl2, CH2Br2, CHBr2Cl, CHBr3, H1301, H1211, H2402, and H1202) were measured, and total organic Br (henceforth called Bryorg) originating from these organic precursors was inferred as a function of altitude. This was compared with total inorganic reactive Br (henceforth called Bryin) derived from spectroscopic BrO observations, after accounting for modeled stratospheric Bry partitioning. Within the studied altitude range the two profiles differed by less than the estimated accumulated uncertainties. This good agreement suggests that the lower stratospheric budget and chemistry of Br is well understood for the specified conditions. For early 1999 our data suggest a Bryin mixing ratio of 1.5 ppt in air just above the local Arctic tropopause (~9.5 km), whilst at 25 km in air of 5.6 yr mean age it was estimated to be 18.4(+1.8/-1.5)ppt from organic precursor measurements, and (21.5+/-3.0)ppt from BrO measurements and photochemical modelling, respectively. This suggests a Bryin influx of 3.1(-2.9/+3.5)ppt from the troposphere to the stratosphere.Geophysical Research Letters 10/2000; 27(20):3305-3308. DOI:10.1029/2000GL011650 · 4.46 Impact Factor
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ABSTRACT: MIPAS (Michelson Interferometer for Passive Atmospheric Sounding), a high resolution limb sounder, is now under construction as an ESA Developed Instrument (EDI) on ESA's planned environmental satellite ENVISAT-1. The feasibility of detecting 27 trace constituents with MIPAS in the middle atmosphere has been studied under a contract with ESA on the basis of simulated limb emission spectra in the mid-i.r. spectral region from 4.15 to 14.6 μm assuming a spectral resolution of 0.05 cm-1. Synthetic emission spectra have been generated for complete limb sequences. For the best suited spectral features, radiance profiles have been calculated for various atmospheric conditions. Based on the present performance parameters of MIPAS, altitude ranges have been estimated in which each constituent can be measured within defined limits of accuracy. The working procedure and the main results of the study on MIPAS' capability to measure the atmospheric composition are presented. While the results are specific to this instrument, they might be of general interest to investigators working in the area of high resolution atmospheric remote sensing.Journal of Quantitative Spectroscopy and Radiative Transfer 09/1994; DOI:10.1016/0022-4073(94)90155-4 · 2.29 Impact Factor
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ABSTRACT: A deeper understanding of long-term ozone trends and periods of significant ozone depletion as well as of the anthropogenic greenhouse effect requires the concerted actions of experimenters and modelers. With respect to observations, atmospheric constituents need to be measured simultaneously and on a global basis. Fourier-transform infrared spectrometers are especially suited for this measurement task. Apromising and challenging branch of Fourier-transform infrared spectroscopy is its application to limb-emission sounding by the use of cryogenic instrumentation. This method allows the measurements to be made independently of the time of the day. The MIPAS (Michelson interferometer for passive atmospheric sounding) balloon-borne (MIPAS-B) and space-based (MIPAS-S) experiments apply this technique. While the MIPAS-B instrument has already been used for several years for stratospheric process studies, the MIPAS-S instrument is in development for the European Space Agency's ENVISAT mission. Instrumental aspects of these MIPAS experiments are highlighted, the most important results in ozone research achieved with MIPAS-B are reviewed, and a brief overview of the scientific capabilities of the MIPAS space experiment is given.Applied Optics 01/1996; 35(16):2787-2796. DOI:10.1364/AO.35.002787 · 1.78 Impact Factor