Solar-forced shifts of the Southern Hemisphere Westerlies during the Holocene

The Southern Hemisphere Westerly Winds (SWW) constitute an important zonal circulation that influences large-scale precipitation patterns and ocean circulation. Variations in their intensity and latitudinal position have been suggested to exert a strong influence on the CO 2 budget in the Southern O...

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Bibliographic Details
Published in:Climate of the Past
Main Authors: Varma, V., Prange, M., Lamy, F., Merkel, U., Schulz, M.
Format: Text
Language:English
Published: 2018
Subjects:
Online Access:https://doi.org/10.5194/cp-7-339-2011
https://cp.copernicus.org/articles/7/339/2011/
Description
Summary:The Southern Hemisphere Westerly Winds (SWW) constitute an important zonal circulation that influences large-scale precipitation patterns and ocean circulation. Variations in their intensity and latitudinal position have been suggested to exert a strong influence on the CO 2 budget in the Southern Ocean, thus making them a potential factor affecting the global climate. In the present study, the possible influence of solar forcing on SWW variability during the Holocene is addressed. It is shown that a high-resolution iron record from the Chilean continental slope (41° S), which is interpreted to reflect changes in the position of the SWW, is significantly correlated with reconstructed solar activity during the past 3000 years. In addition, solar sensitivity experiments with a comprehensive global climate model (CCSM3) were carried out to study the response of SWW to solar variability. Taken together, the proxy and model results suggest that centennial-scale periods of lower (higher) solar activity caused equatorward (southward) shifts of the annual mean SWW.