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: The Polar Ozone and Aerosol Measurement (POAM) III instrument operated continuously during the Stratospheric Aerosol and Gas Experiment (SAGE) III Ozone Loss and Validation Experiment (SOLVE) mission, making approximately 1400 ozone profile measurements at high latitudes both inside and outside the Arctic polar vortex. The wealth of ozone measurements obtained from a variety of instruments and platforms during SOLVE provided a unique opportunity to compare correlative measurements with the POAM III data set. In this paper, we validate the POAM III version 3.0 ozone against measurements from seven different instruments that operated as part of the combined SOLVE/THESEO 2000 campaign. These include the airborne UV Differential Absorption Lidar (UV DIAL) and the Airborne Raman Ozone and Temperature Lidar (AROTEL) instruments on the DC-8, the dual-beam UV-Absorption Ozone Photometer on the ER-2, the MkIV Interferometer balloon instrument, the Laboratoire de Physique Molèculaire et Applications and Differential Optical Absorption Spectroscopy (LPMA/DOAS) balloon gondola, the JPL in situ ozone instrument on the Observations of the Middle Stratosphere (OMS) balloon platform, and the Système D'Analyze par Observations Zénithales (SAOZ) balloon sonde. The resulting comparisons show a remarkable degree of consistency despite the very different measurement techniques inherent in the data sets and thus provide a strong validation of the POAM III version 3.0 ozone. This is particularly true in the primary 14–30 km region, where there are significant overlaps with all seven instruments. At these altitudes, POAM III agrees with all the data sets to within 7–10% with no detectable bias. The observed differences are within the combined errors of POAM III and the correlative measurements. Above 30 km, only a handful of SOLVE correlative measurements exist and the comparisons are highly variable. Therefore, the results are inconclusive. Below 14 km, the SOLVE comparisons also show a large amount of scatter and it is difficult to evaluate their consistency, although the number of correlative measurements is large. The UV DIAL, DOAS, and JPL/OMS comparisons show differences of up to 15% but no consistent bias. The ER-2, MkIV, and SAOZ comparisons, on the other hand, indicate a high POAM bias of 10–20% at the lower altitudes. In general, the SOLVE validation results presented here are consistent with the validation of the POAM III version 3.0 ozone using SAGE II and Halogen Occultation Experiment (HALOE) satellite data and in situ electrochemical cell (ECC) ozonesonde data.Journal of Geophysical Research: Atmospheres. 01/2002; 107(D5):SOL 59-1-SOL 59-21.
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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. · 3.98 Impact Factor
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ABSTRACT: Vertical profiles of N2O5, HO2NO2, and NO2 inside the arctic vortex were retrieved from nighttime infrared limb emission spectra measured by the Michelson Interferometer for Passive Atmospheric Sounding, Balloon-borne version 2 (MIPAS-B2) instrument from Kiruna (Sweden, 68°N) on February 11, 1995, as part of the Second European Stratospheric Arctic and Midlatitude Experiment (SESAME). Spectra were analyzed by a multiparameter nonlinear least squares fitting procedure in combination with an onion-peeling retrieval algorithm. The N2O5, HO2NO2, and NO2 results were derived from spectral features within the bands near 8.0 mum, 12.5 mum, and 6.2 mum, respectively. Peak mixing ratios of 1.14 parts per billion by volume (ppbv) N2O5 and 80 parts per trillion by volume (pptv) HO2NO2 at 17.1 hPa as well as 2.79 ppbv NO2 at 12.0 hPa corresponding to 25.8 km and 28.0 km altitude were inferred from the spectra. NO2 mixing ratios measured by MIPAS fit well to the data observed by concurrent flights. A comparison with calculations performed with a three-dimensional chemistry transport model for the time and location of the measurements shows that the best agreement of measured and calculated profiles is reached between 17 and 28 hPa corresponding to 25.8 and 22.7 km altitude, while below and above this altitude region there are some discrepancies between the modeled and observed data.Journal of Geophysical Research Atmospheres 01/1997; 1021:19177-19186. · 3.44 Impact Factor