Indian summer monsoon forcing on the deglacial polar cold reversals

Banakar, Virupaxa K and Baidya, Sweta and Piotrowski, Alexander M. and Shankar, D (2017) Indian summer monsoon forcing on the deglacial polar cold reversals. Journal of Earth System Science, 126 (6). ISSN 0253-4126 DOI https://doi.org/10.1007/s12040-017-0864-5

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Abstract

The deglacial transition from the last glacial maximum at ∼20 kiloyears before present (ka) to the Holocene (11.7 ka to Present) was interrupted by millennial-scale cold reversals, viz., Antarctic Cold Reversal (∼14.5–12.8 ka) and Greenland Younger Dryas (∼12.8–11.8 ka) which had different timings and extent of cooling in each hemisphere. The cause of this synchronously initiated, but different hemispheric cooling during these cold reversals (Antarctic Cold Reversal ∼3∘C and Younger Dryas ∼10∘C) is elusive because CO2, the fundamental forcing for deglaciation, and Atlantic meridional overturning circulation, the driver of antiphased bipolar climate response, both fail to explain this asymmetry. We use centennial-resolution records of the local surface water δ18O of the Eastern Arabian Sea, which constitutes a proxy for the precipitation associated with the Indian Summer Monsoon, and other tropical precipitation records to deduce the role of tropical forcing in the polar cold reversals. We hypothesize a mechanism for tropical forcing, via the Indian Summer Monsoons, of the polar cold reversals by migration of the Inter-Tropical Convergence Zone and the associated cross-equatorial heat transport.

Item Type: Article
Uncontrolled Keywords: 2017AREP; IA73; Sylvia
Subjects: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Divisions: 01 - Climate Change and Earth-Ocean Atmosphere Systems
Journal or Publication Title: Journal of Earth System Science
Volume: 126
Identification Number: https://doi.org/10.1007/s12040-017-0864-5
Depositing User: Sarah Humbert
Date Deposited: 01 Oct 2017 20:55
Last Modified: 01 Oct 2017 20:55
URI: http://eprints.esc.cam.ac.uk/id/eprint/4059

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