The impact of dehydration and extremely low HCl values in the Antarctic stratospheric vortex in mid-winter on ozone loss in spring

<p>Simulations of Antarctic chlorine and ozone chemistry in previous work show that in the core of the Antarctic vortex (16–18 km, 85–55 hPa, 390–430 K) HCl null cycles (initiated by reactions of Cl with <span class="inline-formula">CH<sub>4</sub></span> and &...

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Main Authors: Y. Zhang-Liu, R. Müller, J.-U. Grooß, S. Robrecht, B. Vogel, A. M. Zafar, R. Lehmann
Format: Article
Language:English
Published: Copernicus Publications 2024-11-01
Series:Atmospheric Chemistry and Physics
Online Access:https://acp.copernicus.org/articles/24/12557/2024/acp-24-12557-2024.pdf
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author Y. Zhang-Liu
R. Müller
R. Müller
J.-U. Grooß
J.-U. Grooß
S. Robrecht
S. Robrecht
B. Vogel
B. Vogel
A. M. Zafar
A. M. Zafar
R. Lehmann
author_facet Y. Zhang-Liu
R. Müller
R. Müller
J.-U. Grooß
J.-U. Grooß
S. Robrecht
S. Robrecht
B. Vogel
B. Vogel
A. M. Zafar
A. M. Zafar
R. Lehmann
author_sort Y. Zhang-Liu
collection DOAJ
description <p>Simulations of Antarctic chlorine and ozone chemistry in previous work show that in the core of the Antarctic vortex (16–18 km, 85–55 hPa, 390–430 K) HCl null cycles (initiated by reactions of Cl with <span class="inline-formula">CH<sub>4</sub></span> and <span class="inline-formula">CH<sub>2</sub>O</span>) are effective. These HCl null cycles cause both HCl molar mixing ratios to remain very low throughout Antarctic winter and spring. They cause ozone-destroying chlorine (<span class="inline-formula">ClO<sub><i>x</i></sub></span>) to remain enhanced so that rapid ozone depletion proceeds. Here we investigate the impact of the observed dehydration in Antarctica, which strongly reduces ice formation and the uptake of <span class="inline-formula">HNO<sub>3</sub></span> from the gas phase; however the efficacy of HCl null cycles is not affected. Moreover, also when using the observed very low HCl molar mixing ratios in Antarctic winter as an initial value, HCl null cycles are efficient in maintaining low HCl (and high <span class="inline-formula">ClO<sub><i>x</i></sub></span>) throughout winter and spring. Further, the reaction <span class="inline-formula">CH<sub>3</sub>O<sub>2</sub>+ClO</span> is important for the efficacy of the HCl null cycle initiated by the reaction <span class="inline-formula">CH<sub>4</sub>+Cl</span>. Using the current kinetic recommendations instead of earlier ones has very little impact on the simulations. All simulations presented here for the core of the Antarctic vortex show extremely low minimum ozone values (below 50 ppb) in late September to early October in agreement with observations.</p>
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language English
publishDate 2024-11-01
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spelling doaj-art-b0facf1f0b714a2c95b1b26a17bfe5d62024-11-14T08:34:12ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242024-11-0124125571257410.5194/acp-24-12557-2024The impact of dehydration and extremely low HCl values in the Antarctic stratospheric vortex in mid-winter on ozone loss in springY. Zhang-Liu0R. Müller1R. Müller2J.-U. Grooß3J.-U. Grooß4S. Robrecht5S. Robrecht6B. Vogel7B. Vogel8A. M. Zafar9A. M. Zafar10R. Lehmann11Institute of Climate and Energy Systems: Stratosphere (ICE-4), Forschungszentrum Jülich, Jülich, GermanyInstitute of Climate and Energy Systems: Stratosphere (ICE-4), Forschungszentrum Jülich, Jülich, GermanyCentre for Advanced Simulation and Analytics (CASA), Forschungszentrum Jülich, Jüich, GermanyInstitute of Climate and Energy Systems: Stratosphere (ICE-4), Forschungszentrum Jülich, Jülich, GermanyCentre for Advanced Simulation and Analytics (CASA), Forschungszentrum Jülich, Jüich, GermanyInstitute of Climate and Energy Systems: Stratosphere (ICE-4), Forschungszentrum Jülich, Jülich, GermanyKlima und Umwelt, Deutscher Wetterdienst, Offenbach, GermanyInstitute of Climate and Energy Systems: Stratosphere (ICE-4), Forschungszentrum Jülich, Jülich, GermanyCentre for Advanced Simulation and Analytics (CASA), Forschungszentrum Jülich, Jüich, GermanyInstitute of Climate and Energy Systems: Stratosphere (ICE-4), Forschungszentrum Jülich, Jülich, GermanyBiotechnology Research Center, Technology Innovation Institute, Masdar City, Abu Dhabi, United Arab EmiratesAlfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, Potsdam, Germany<p>Simulations of Antarctic chlorine and ozone chemistry in previous work show that in the core of the Antarctic vortex (16–18 km, 85–55 hPa, 390–430 K) HCl null cycles (initiated by reactions of Cl with <span class="inline-formula">CH<sub>4</sub></span> and <span class="inline-formula">CH<sub>2</sub>O</span>) are effective. These HCl null cycles cause both HCl molar mixing ratios to remain very low throughout Antarctic winter and spring. They cause ozone-destroying chlorine (<span class="inline-formula">ClO<sub><i>x</i></sub></span>) to remain enhanced so that rapid ozone depletion proceeds. Here we investigate the impact of the observed dehydration in Antarctica, which strongly reduces ice formation and the uptake of <span class="inline-formula">HNO<sub>3</sub></span> from the gas phase; however the efficacy of HCl null cycles is not affected. Moreover, also when using the observed very low HCl molar mixing ratios in Antarctic winter as an initial value, HCl null cycles are efficient in maintaining low HCl (and high <span class="inline-formula">ClO<sub><i>x</i></sub></span>) throughout winter and spring. Further, the reaction <span class="inline-formula">CH<sub>3</sub>O<sub>2</sub>+ClO</span> is important for the efficacy of the HCl null cycle initiated by the reaction <span class="inline-formula">CH<sub>4</sub>+Cl</span>. Using the current kinetic recommendations instead of earlier ones has very little impact on the simulations. All simulations presented here for the core of the Antarctic vortex show extremely low minimum ozone values (below 50 ppb) in late September to early October in agreement with observations.</p>https://acp.copernicus.org/articles/24/12557/2024/acp-24-12557-2024.pdf
spellingShingle Y. Zhang-Liu
R. Müller
R. Müller
J.-U. Grooß
J.-U. Grooß
S. Robrecht
S. Robrecht
B. Vogel
B. Vogel
A. M. Zafar
A. M. Zafar
R. Lehmann
The impact of dehydration and extremely low HCl values in the Antarctic stratospheric vortex in mid-winter on ozone loss in spring
Atmospheric Chemistry and Physics
title The impact of dehydration and extremely low HCl values in the Antarctic stratospheric vortex in mid-winter on ozone loss in spring
title_full The impact of dehydration and extremely low HCl values in the Antarctic stratospheric vortex in mid-winter on ozone loss in spring
title_fullStr The impact of dehydration and extremely low HCl values in the Antarctic stratospheric vortex in mid-winter on ozone loss in spring
title_full_unstemmed The impact of dehydration and extremely low HCl values in the Antarctic stratospheric vortex in mid-winter on ozone loss in spring
title_short The impact of dehydration and extremely low HCl values in the Antarctic stratospheric vortex in mid-winter on ozone loss in spring
title_sort impact of dehydration and extremely low hcl values in the antarctic stratospheric vortex in mid winter on ozone loss in spring
url https://acp.copernicus.org/articles/24/12557/2024/acp-24-12557-2024.pdf
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