M. Ackerman, D. Frimout, A. Girard, M. Gottignies, and C. Muller. Stratospheric HCl from infrared spectra. Geophysical Research Letters, 3:81-83, February 1976. [ bib | DOI | ADS link ]
HCl has been observed in the stratosphere from balloon borne spectroscopic measurements of a portion of the fundamental band in the 3 microns wavelength region. The observation of absorption lines using the sun as a source at solar zenith angles larger than 90deg indicates an HCl volume mixing ratio equal to (3.8 1.5) × 10-10 at 20 km increasing with altitude at least up to 30 km where the value is (1.4 0.6) × 10-9. The total zenith amount above 21 km is found to be (10 3.5) × 10-14 cm-2 in agreement with previous observations performed up to this altitude. A maximum number density equal to (7.2 3) × 108 cm-3 is observed at 24 2 km altitude.