The ‘sticky’ ITCZ: ocean-moderated ITCZ shifts
Name
StickyITCZ.pdf
Description
Accepted version
Size
1.77 MB
Format
Adobe PDF
Checksum (MD5)
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Author(s)
Green, Brian Marcus
Marshall, John C
Campin, Jean-Michel
Date Issued
January 2019
Journal
Climate Dynamics
Publisher
Springer Science and Business Media LLC
Citation
Green, Brian et al. "The ‘sticky’ ITCZ: ocean-moderated ITCZ shifts." Climate Dynamics 53, 1-2 (January 2019): 1–19 © 2019 Springer-Verlag GmbH Germany, part of Springer Nature
Version
Author's final manuscript
Abstract
Across a range of simulations with a coupled atmosphere–ocean climate model, shifts in the intertropical convergence zone (ITCZ) are induced by an interhemispheric heating contrast. The response to heating anomalies which are polar amplified are contrasted with those which are largest in the tropics. First, we find that ITCZ shifts are always damped relative to simulations in which the ocean circulation is held fixed, irrespective of the heating distribution, keeping the ITCZ “stuck” to latitudes near the equator. The damping is primarily due to the ocean’s anomalous cross-equatorial energy transport associated with the coupling of the trade winds to an oceanic cross-equatorial cell (CEC). Second, we find that the damping effect is strongest when the forcing distribution is polar-amplified, which enhances the gross stability of the CEC and maximizes the efficiency of its cross-equatorial energy transport. Third, we argue that the ocean’s energy transport can have secondary impacts on ITCZ shifts through its interaction with climate feedbacks. Finally, we discuss the implications of our study for our understanding of the role of CECs in damping ITCZ shifts and the atmosphere’s energy balance.
MIT Department
Massachusetts Institute of Technology. Department of Earth, Atmospheric, and Planetary Sciences
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Creative Commons Attribution-Noncommercial-Share Alike
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DOI of Published Version
https://doi.org/10.1007/s00382-019-04623-5
