Technical note: Multi-year changes in the Brewer–Dobson circulation from Halogen Occultation Experiment (HALOE) methane

<p>This study makes use of Halogen Occultation Experiment (HALOE) methane (CH<span class="inline-formula"><sub>4</sub></span>) in a search for multi-year changes in the Brewer–Dobson circulation (BDC). Changes in CH<span class="inline-formula">...

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Main Author: E. Remsberg
Format: Article
Language:English
Published: Copernicus Publications 2024-02-01
Series:Atmospheric Chemistry and Physics
Online Access:https://acp.copernicus.org/articles/24/1691/2024/acp-24-1691-2024.pdf
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author E. Remsberg
author_facet E. Remsberg
author_sort E. Remsberg
collection DOAJ
description <p>This study makes use of Halogen Occultation Experiment (HALOE) methane (CH<span class="inline-formula"><sub>4</sub></span>) in a search for multi-year changes in the Brewer–Dobson circulation (BDC). Changes in CH<span class="inline-formula"><sub>4</sub></span> are determined for three successive 5-year time spans from 1992 to 2005, and there are significant differences between them. There is a clear separation between the changes in the Northern Hemisphere near 30 hPa and at the transition of the shallow and deep branches of the BDC. The CH<span class="inline-formula"><sub>4</sub></span> changes are positive and large in the shallow branch following the eruption of Pinatubo, but they then decrease and agree with tropospheric trends in the late 1990s and early 2000s. CH<span class="inline-formula"><sub>4</sub></span> decreases in the upper part of the deep branch from 1992 to 1997 or following the eruption of Pinatubo. CH<span class="inline-formula"><sub>4</sub></span> continues to decrease in the deep branch in the late 1990s but then increases in the early 2000s, although those changes are small compared with the seasonal and interannual variations of CH<span class="inline-formula"><sub>4</sub></span>. Multi-year changes are due, in part, to wave forcings during the El Niño–Southern Oscillation (ENSO) of 1997–1998 and beyond and to episodic, sudden stratospheric warming (SSW) events during both time spans. It is concluded that time series of HALOE CH<span class="inline-formula"><sub>4</sub></span> provide effective tracer diagnostics for studies of the nature of the BDC from 1992 to 2005.</p>
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spelling doaj.art-2b9fce8a0ced43cfa060e3debcc0a1dc2024-02-06T13:29:20ZengCopernicus PublicationsAtmospheric Chemistry and Physics1680-73161680-73242024-02-01241691169710.5194/acp-24-1691-2024Technical note: Multi-year changes in the Brewer–Dobson circulation from Halogen Occultation Experiment (HALOE) methaneE. Remsberg<p>This study makes use of Halogen Occultation Experiment (HALOE) methane (CH<span class="inline-formula"><sub>4</sub></span>) in a search for multi-year changes in the Brewer–Dobson circulation (BDC). Changes in CH<span class="inline-formula"><sub>4</sub></span> are determined for three successive 5-year time spans from 1992 to 2005, and there are significant differences between them. There is a clear separation between the changes in the Northern Hemisphere near 30 hPa and at the transition of the shallow and deep branches of the BDC. The CH<span class="inline-formula"><sub>4</sub></span> changes are positive and large in the shallow branch following the eruption of Pinatubo, but they then decrease and agree with tropospheric trends in the late 1990s and early 2000s. CH<span class="inline-formula"><sub>4</sub></span> decreases in the upper part of the deep branch from 1992 to 1997 or following the eruption of Pinatubo. CH<span class="inline-formula"><sub>4</sub></span> continues to decrease in the deep branch in the late 1990s but then increases in the early 2000s, although those changes are small compared with the seasonal and interannual variations of CH<span class="inline-formula"><sub>4</sub></span>. Multi-year changes are due, in part, to wave forcings during the El Niño–Southern Oscillation (ENSO) of 1997–1998 and beyond and to episodic, sudden stratospheric warming (SSW) events during both time spans. It is concluded that time series of HALOE CH<span class="inline-formula"><sub>4</sub></span> provide effective tracer diagnostics for studies of the nature of the BDC from 1992 to 2005.</p>https://acp.copernicus.org/articles/24/1691/2024/acp-24-1691-2024.pdf
spellingShingle E. Remsberg
Technical note: Multi-year changes in the Brewer–Dobson circulation from Halogen Occultation Experiment (HALOE) methane
Atmospheric Chemistry and Physics
title Technical note: Multi-year changes in the Brewer–Dobson circulation from Halogen Occultation Experiment (HALOE) methane
title_full Technical note: Multi-year changes in the Brewer–Dobson circulation from Halogen Occultation Experiment (HALOE) methane
title_fullStr Technical note: Multi-year changes in the Brewer–Dobson circulation from Halogen Occultation Experiment (HALOE) methane
title_full_unstemmed Technical note: Multi-year changes in the Brewer–Dobson circulation from Halogen Occultation Experiment (HALOE) methane
title_short Technical note: Multi-year changes in the Brewer–Dobson circulation from Halogen Occultation Experiment (HALOE) methane
title_sort technical note multi year changes in the brewer dobson circulation from halogen occultation experiment haloe methane
url https://acp.copernicus.org/articles/24/1691/2024/acp-24-1691-2024.pdf
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