Dow, WJ orcid.org/0000-0002-3285-5340, Maycock, AC orcid.org/0000-0002-6614-1127, Lofverstrom, M et al. (1 more author) (2021) The effect of anthropogenic aerosols on the Aleutian Low. Journal of Climate, 34 (5). pp. 1725-1741. ISSN 0894-8755
Abstract
Past studies have suggested that regional trends in anthropogenic aerosols can influence the Pacific decadal oscillation (PDO) through modulation of the Aleutian low. However, the robustness of this connection is debated. This study analyzes changes to the Aleutian low in an ensemble of climate models forced with large, idealized global and regional black carbon (BC) and sulfate aerosol perturbations. To isolate the role of ocean feedbacks, the experiments are performed with an interactive ocean and with prescribed sea surface temperatures. The results show a robust weakening of the Aleutian low forced by a global tenfold increase in BC in both experiment configurations. A linearized steady-state primitive equation model is forced with diabatic heating anomalies to investigate the mechanisms through which heating from BC emissions influences the Aleutian low. The heating from BC absorption over India and East Asia generates Rossby wave trains that propagate into the North Pacific sector, forming an upper-tropospheric ridge. Sources of BC outside of East Asia enhance the weakening of the Aleutian low. The responses to a global fivefold and regional tenfold increase in sulfate aerosols over Asia show poor consistency across climate models, with a multimodel mean response that does not project strongly onto the Aleutian low. These findings for a large, idealized step increase in regional sulfate aerosol differ from previous studies that suggest the transient increase in sulfate aerosols over Asia during the early twenty-first century weakened the Aleutian low and induced a transition to a negative PDO phase.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2021 American Meteorological Society. Permission to use figures, tables, and brief excerpts from this work in scientific and educational works is hereby granted provided that the source is acknowledged. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC §108) does not require the AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a website or in a searchable database, or other uses of this material, except as exempted by the above statement, requires written permission or a license from the AMS. All AMS journals and monograph publications are registered with the Copyright Clearance Center (http://www.copyright.com). Questions about permission to use materials for which AMS holds the copyright can also be directed to permissions@ametsoc.org. Additional details are provided in the AMS Copyright Policy statement, available on the AMS website (http://www.ametsoc.org/CopyrightInformation). |
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) |
Funding Information: | Funder Grant number NERC (Natural Environment Research Council) NE/M018199/1 EU - European Union 820829 Leverhulme Trust PLP-2018-278 NERC (Natural Environment Research Council) NE/T009381/1 |
Depositing User: | Symplectic Publications |
Date Deposited: | 27 Nov 2020 14:02 |
Last Modified: | 30 Mar 2021 11:22 |
Status: | Published |
Publisher: | American Meteorological Society |
Identification Number: | 10.1175/JCLI-D-20-0423.1 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:168245 |