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Monsoons as eddy-mediated regime transitions of the tropical overturning circulation

Bordoni, Simona and Schneider, Tapio (2008) Monsoons as eddy-mediated regime transitions of the tropical overturning circulation. Nature Geoscience, 1 (8). pp. 515-519. ISSN 1752-0894. doi:10.1038/ngeo248. https://resolver.caltech.edu/CaltechAUTHORS:BORng08

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Abstract

Monsoons are generally viewed as planetary-scale sea-breeze circulations, caused by contrasts in the thermal properties between oceans and land surfaces that lead to thermal contrasts upon radiative heating1, 2. But the radiative heating evolves gradually with the seasons, whereas the onset of monsoon precipitation, and the associated circulation changes such as reversal of surface winds, occur rapidly3, 4. Here we use reanalysis data to show that the onset of the Asian monsoon marks a transition between two circulation regimes that are distinct in the degree to which eddy momentum fluxes control the strength of the tropical overturning circulation. Rapid transitions of the circulation between the two regimes can occur as a result of feedbacks between large-scale extratropical eddies and the tropical circulation5. Using simulations with an aquaplanet general circulation model, we demonstrate that rapid, eddy-mediated monsoon transitions occur even in the absence of surface inhomogeneities, provided the planet surface has sufficiently low thermal inertia. On the basis of these results, we propose a view of monsoons in which feedbacks between large-scale extratropical eddies and the tropical circulation are essential for the development of monsoons, whereas surface inhomogeneities such as land-sea contrasts are not.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1038/ngeo248DOIUNSPECIFIED
http://www.nature.com/ngeo/journal/v1/n8/abs/ngeo248.htmlPublisherUNSPECIFIED
ORCID:
AuthorORCID
Bordoni, Simona0000-0003-4771-3350
Schneider, Tapio0000-0001-5687-2287
Contact Email Address:bordoni@gps.caltech.edu
Additional Information:© 2008 Nature Publishing Group. Received 6 February 2008; accepted 4 June 2008; published 6 July 2008. This work was supported by the Davidow Discovery Fund, a David and Lucile Packard Fellowship, a Moore Postdoctoral Fellowship and the National Science Foundation (grant no. ATM-0450059). The simulations were carried out on Caltech’s Geological and Planetary Science Dell Cluster, and the reanalysis data were provided by the National Center for Atmospheric Research (which is sponsored by the National Science Foundation). Part of the research was carried while S.B. was with the Department of Atmospheric and Oceanic Sciences at UCLA (supported by a UCLA Dissertation Year Fellowship). We thank B. Stevens for comments on drafts of this paper.
Funders:
Funding AgencyGrant Number
Davidow Discovery FundUNSPECIFIED
David and Lucile Packard FoundationUNSPECIFIED
Gordon and Betty Moore FoundationUNSPECIFIED
National Science FoundationATM-0450059
UCLA Dissertation Year FellowshipUNSPECIFIED
Issue or Number:8
DOI:10.1038/ngeo248
Record Number:CaltechAUTHORS:BORng08
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:BORng08
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:11753
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:23 Sep 2008 02:37
Last Modified:08 Nov 2021 22:02

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