Stratospheric HCl from infrared spectra

Abstract

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 90° 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.

Validation of ACE-FTS v2.2 measurements of HCl, HF, CCl<sub>3</sub>F and CCl<sub>2</sub>F<sub>2</sub> using space-, balloon- and ground-based instrument observations

“…These increasing tropospheric loadings were at the heart of the alarming threat to ozone suggested by Molina and Rowland (1974). This theory was soon supported by the first detections in the stratosphere of HF (Zander et al, 1975), of HCl (Farmer et al, 1976;Ackerman et al, 1976), and of CFC-11 and -12 (Murcray et al, 1975).…”

Chemistry of Stratospheric Chlorine

“…The calculated HCl profile can reproduce fairly well the observations by Lazrus et al (1975), Farmer et al (1976) and Ackerman et al (1976). This implies the stratospheric source of ClOx from the chlorocarbons can provide enough HCl to account for the observed HCl content.…”

“…This result has been obtained by as- Fig. 4 Calculated height distributions of HCl and ClX (=ClOx + HCl) densities, together with the measured densities of HCl by Lazrus et al (1975), Farmer et al (1976 and Ackerman et al (1976).…”

Long‐term trends of inorganic chlorine from ground‐based infrared solar spectra: Past increases and evidence for stabilization

“…[4] High spectral resolution infrared solar absorption spectrometry has long been recognized as a key technique for remotely measuring atmospheric HCl from the ground, airplanes, and balloons [Farmer et al, 1976;Ackerman et al, 1976;Mankin and Coffey, 1983] and subsequently from space [e.g., Raper et al, 1987;Zander et al, 1992Zander et al, , 1996Gunson et al, 1994;Russell et al, 1996] by observing the strong HCl (1 -0) band transitions located near 3 mm. Past investigations of HCl trends from long-term ground-based monitoring include the studies by Zander et al [1987], Rinsland et al [1991], Wallace and Livingston [1991], and Wallace et al [1997].…”