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

• Published in: Climate of the Past
• Main Authors: Varma, V., Prange, M., Lamy, F., Merkel, U., Schulz, M.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2011
• Subjects: article; Verlagsveröffentlichung; Southern Ocean
• Online Access: https://doi.org/10.5194/cp-7-339-2011; https://noa.gwlb.de/receive/cop_mods_00027589; https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00027544/cp-7-339-2011.pdf; https://cp.copernicus.org/articles/7/339/2011/cp-7-339-2011.pdf

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 CO2 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.