Articles | Volume 22, issue 7
Atmos. Chem. Phys., 22, 4779–4799, 2022
Atmos. Chem. Phys., 22, 4779–4799, 2022
Research article
12 Apr 2022
Research article | 12 Apr 2022

Upper stratospheric ClO and HOCl trends (2005–2020): Aura Microwave Limb Sounder and model results

Lucien Froidevaux et al.

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Cited articles

Anderson, J., Margitan, J. J., and Stedman, D. H.: Atomic Chlorine and the Chlorine Monoxide Radical in the Stratosphere: Three in situ Observations, Science, 198, 4316,, 1977. 
Anderson, J., Russell III, J. M., Solomon, S., and Deaver, L. E.: Halogen Occultation Experiment confirmation of stratospheric chlorine decreases in accordance with the Montreal Protocol, J. Geophys. Res., 105, 4483–4490, 2000. 
Bernath, P. F.: The Atmospheric Chemistry Experiment (ACE), J. Quant. Spectrosc. Ra., 186, 3–16,, 2017. 
Bernath, P. and Fernando, A. M.: Trends in stratospheric HCl from the ACE satellite mission, J. Quant. Spectrosc. Ra., 217, 126–129,, 2018. 
Bernath P. F., Steffen J., Crouse J., and Boone C. D.: Sixteen-year trends in atmospheric trace gases from orbit, J. Quant. Spectrosc. Ra. 253, 107178,, 2020a. 
Short summary
We analyze satellite-derived distributions of chlorine monoxide (ClO) and hypochlorous acid (HOCl) in the upper atmosphere. For 2005–2020, from 50°S to 50°N and over ~30 to 45 km, ClO and HOCl decreased by −0.7 % and −0.4 % per year, respectively. A detailed model of chemistry and dynamics agrees with the results. These decreases confirm the effectiveness of the 1987 Montreal Protocol, which limited emissions of chlorine- and bromine-containing source gases, in order to protect the ozone layer.
Final-revised paper