Journal article
Suppression of Atlantic meridional overturning circulation variability at increased CO2
- Abstract:
- Multidecadal variability in the Atlantic meridional overturning circulation (AMOC) is shown to differ significantly between the 4 × CO2 and preindustrial control simulations of the GFDL Earth System Model, version 2M (ESM2M) general circulation model (GCM). In the preindustrial simulation, this model has a peak in the power spectrum of both AMOC and northward heat transport at latitudes between 26° and 50°N. In the 4 × CO2 simulation, the only significant spectral peak is near 60°N. Understanding these differences is important for understanding the effect of future climate change on climate variability, as well as for providing insight into the physics underlying AMOC variability. Transfer function analysis demonstrates that the shift is predominantly due to a shift in the internal ocean dynamics rather than a change in stochastic atmospheric forcing. Specifically, the reduction in variance from 26° to 45°N is due to an increased stratification east of Newfoundland that results from the shallower and weaker mean overturning. The reduced AMOC variance that accompanies the reduced mean value of the AMOC at 4 × CO2 differs from predictions of simple box models that predict a weaker circulation to be closer to a stability bifurcation point and, therefore, be accompanied by amplified variability. The high-latitude variability in the 4 × CO2 simulation is related to the advection of anomalies by the subpolar gyre, distinct from the variability mechanism in the control simulation at lower latitudes. The 4 × CO2 variability has only a small effect on midlatitude meridional heat transport, but does significantly affect sea ice in the northern North Atlantic.
- Publication status:
- Published
- Peer review status:
- Peer reviewed
Actions
Access Document
- Files:
-
-
(Preview, Version of record, pdf, 1.9MB, Terms of use)
-
- Publisher copy:
- 10.1175/JCLI-D-15-0533.1
Authors
- Publisher:
- American Meteorological Society
- Journal:
- Journal of Climate More from this journal
- Volume:
- 29
- Issue:
- 11
- Pages:
- 4155-4164
- Publication date:
- 2016-05-20
- Acceptance date:
- 2016-02-26
- DOI:
- EISSN:
-
1520-0442
- ISSN:
-
0894-8755
- Keywords:
- Pubs id:
-
pubs:618481
- UUID:
-
uuid:3c2a8adf-b114-4e4c-b475-1d12883ac68b
- Local pid:
-
pubs:618481
- Source identifiers:
-
618481
- Deposit date:
-
2016-04-29
- ARK identifier:
Terms of use
- Copyright holder:
- American Meteorological Society
- Copyright date:
- 2016
- Notes:
- © Copyright 2015-05-20 American Meteorological Society (AMS). 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 the AMS Permissions Officer at [email protected]. Additional details are provided in the AMS Copyright Policy statement, available on the AMS website (http://www.ametsoc.org/CopyrightInformation).
If you are the owner of this record, you can report an update to it here: Report update to this record