Zhao, X, Allen, RJ, Wood, T orcid.org/0000-0002-6049-5805 et al. (1 more author) (2020) Tropical belt width proportionately more sensitive to aerosols than greenhouse gases. Geophysical Research Letters, 47 (7). e2019GL086425. ISSN 0094-8276
Abstract
The tropical belt has widened during the last several decades, and both internal variability and anthropogenic forcings have contributed. Although greenhouse gases and stratospheric ozone depletion have been implicated as primary anthropogenic drivers of tropical expansion, the possible role of other drivers remains uncertain. Here, we analyze the tropical belt width response to idealized perturbations in multiple models. Our results show that absorbing black carbon (BC) aerosol drives tropical expansion, and scattering sulfate aerosol drives contraction. BC, especially from Asia, is more efficient per unit radiative forcing than greenhouse gases in driving tropical expansion, particularly in the Northern Hemisphere. Tropical belt expansion (contraction) is associated with an increase (decrease) in extratropical static stability induced by absorbing (scattering) aerosol. Although a formal attribution is difficult, scaling the normalized expansion rates to the historical time period suggests that BC is the largest driver of the Northern Hemisphere tropical widening but with relatively large uncertainty.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | ©2020. American Geophysical Union. All Rights Reserved. This is an author produced version of a paper published in Geophysical Research Letters. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | tropical belt width; anthropogenic drivers; greenhouse gases; aerosols; PDRMIP |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst for Climate & Atmos Science (ICAS) (Leeds) |
Depositing User: | Symplectic Publications |
Date Deposited: | 17 Mar 2020 13:26 |
Last Modified: | 18 Sep 2020 00:38 |
Status: | Published |
Publisher: | American Geophysical Union |
Identification Number: | 10.1029/2019GL086425 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:158475 |