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

• Published in: Climate of the Past
• Main Authors: V. Varma, M. Prange, F. Lamy, U. Merkel, M. Schulz
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2011
• Subjects: Environmental pollution; TD172-193.5; Environmental protection; TD169-171.8; Environmental sciences; GE1-350; Southern Ocean
• Online Access: https://doi.org/10.5194/cp-7-339-2011; https://doaj.org/article/9ad4f18218814105b6f30a8a294eea26

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.