New Insights on the Impact of Ozone‐Depleting Substances on the Brewer‐Dobson Circulation
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PDF Datastream(1).pdf
Description
Published version
Size
6.14 MB
Format
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Checksum (MD5)
441f3ffa2834e72aa58173a5fd1efbec
Author(s)
Abalos, Marta
Polvani, Lorenzo
Calvo, Natalia
Kinnison, Douglas
Ploeger, Felix
Randel, William
Solomon, Susan
Date Issued
2019
Journal
Journal of Geophysical Research: Atmospheres
Publisher
American Geophysical Union (AGU)
Version
Final published version
Abstract
©2019. American Geophysical Union. All Rights Reserved. It has recently been recognized that, in addition to greenhouse gases, anthropogenic emissions of ozone-depleting substances (ODS) can induce long-term trends in the Brewer-Dobson circulation (BDC). Several studies have shown that a substantial fraction of the residual circulation acceleration over the last decades of the twentieth century can be attributed to increasing ODS. Here the mechanisms of this influence are examined, comparing model runs to reanalysis data and evaluating separately the residual circulation and mixing contributions to the mean age of air trends. The effects of ozone depletion in the Antarctic lower stratosphere are found to dominate the ODS impact on the BDC, while the direct radiative impact of these substances is negligible over the period of study. We find qualitative agreement in austral summer BDC trends between model and reanalysis data and show that ODS are the main driver of both residual circulation and isentropic mixing trends over the last decades of the twentieth century. Moreover, aging by isentropic mixing is shown to play a key role on ODS-driven age of air trends.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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DOI of Published Version
https://doi.org/10.1029/2018JD029301
