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

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 δ18O, we show that the North Pacific subpolar gyre ex...

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Bibliographic Details
Published in:Geophysical Research Letters
Main Authors: Gray, William Robert, Wills, Robert C. J., Rae, James William Buchanan, Burke, Andrea, Ivanovic, Ruza F., Roberts, William Henry Gordon, Ferreira, David, Valdes, Paul
Format: Article in Journal/Newspaper
Language:English
Published: American Geophysical Union 2020
Subjects:
Pacific
Ice Sheet
Online Access:https://centaur.reading.ac.uk/87821/
https://centaur.reading.ac.uk/87821/1/Gray_etal_20.pdf
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Summary: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 δ18O, we show that the North Pacific subpolar gyre extended ~3 degrees 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.

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