STRATOSPHERIC N2O5,CH4, AND N2O PROFILES FROM IR SOLAR OCCULTATION SPECTRA

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-degrees-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 4.32 x 10(-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 1.64 +/- 0.49 at 37.5 km, 1.92 +/- 0.56 at 35.5 km, 2.06 +/- 0.47 at 33.5 km, 1.95 +/- 0.42 at 31.5 km, 1.60 +/- 0.33 at 29.5 km, 1.26 +/- 0.28 at 27.5 km, and 0.85 +/- 0.20 at 25.5 km. Error bars indicate the estimated 1-sigma 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.