Wind-driven evolution of the North Pacific subpolar gyre over the last deglaciation

This is a Preprint and has not been peer reviewed. The published version of this Preprint is available: https://doi.org/10.1029/2019GL086328. This is version 2 of this Preprint.

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Authors

William R Gray , Robert C. Jnglin Wills , James W.B. Rae, Andrea Burke, Ruza Ivanovic, William H.G. Roberts, David Ferreira, Paul J Valdes

Abstract

North Pacific atmospheric and oceanic circulations are key missing pieces in our understanding of the reorganisation of the global climate system since the Last Glacial Maximum (LGM). Here, using a basin-wide compilation of planktic foraminiferal oxygen isotopes, we show that the North Pacific subpolar gyre extended ~3° further south during the LGM, consistent with sea surface temperature and productivity proxy data. Analysis of an ensemble of climate models indicates that the expansion of the subpolar gyre was associated with a substantial gyre strengthening. These gyre circulation changes were driven by a southward shift in the mid-latitude westerlies and increased wind-stress from the polar easterlies. Using single-forcing model runs, we show these atmospheric circulation changes are a non-linear response to the combined topographic and albedo effects of the Laurentide Ice Sheet. Our reconstruction suggests the gyre boundary (and thus westerly winds) began to migrate northward at ~17-16 ka, during Heinrich Stadial 1.

DOI

https://doi.org/10.31223/osf.io/jm7vx

Subjects

Climate, Earth Sciences, Oceanography and Atmospheric Sciences and Meteorology, Physical Sciences and Mathematics

Keywords

climate models, oxygen isotopes, deglaciation, gyre circulation, North Pacific, westerlies

Dates

Published: 2019-11-27 04:58

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License

CC BY Attribution 4.0 International

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