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A 250-year periodicity in Southern Hemisphere westerly winds over the last 2600 years

A 250-year periodicity in Southern Hemisphere westerly winds over the last 2600 years Thumbnail


Abstract

Southern Hemisphere westerly airflow has a significant influence on the ocean-atmosphere system of the mid-to high latitudes with potentially global climate implications. Unfortunately, historic observations only extend back to the late 19th century, limiting our understanding of multi-decadal to centennial change. Here we present a highly resolved (30-year) record of past westerly wind strength from a Falkland Islands peat sequence spanning the last 2600 years. Situated within the core latitude of Southern Hemisphere westerly airflow (the so-called furious fifties), we identify highly variable changes in exotic pollen and charcoal derived from South America which can be used to inform on past westerly air strength. We find a period of high charcoal content between 2000 and 1000 cal. years BP, associated with increased burning in Patagonia, most probably as a result of higher temperatures and stronger westerly airflow. Spectral analysis of the charcoal record identifies a pervasive ca. 250-year periodicity that is coherent with radiocarbon production rates, suggesting that solar variability has a modulating influence on Southern Hemisphere westerly airflow. Our results have important implications for understanding global climate change through the late Holocene.

Citation

(2016). A 250-year periodicity in Southern Hemisphere westerly winds over the last 2600 years. Climate of the Past, 189 -200. https://doi.org/10.5194/cp-12-189-2016

Acceptance Date Jan 17, 2016
Publication Date Feb 3, 2016
Journal Climate of the Past
Print ISSN 1814-9324
Publisher European Geosciences Union (EGU)
Pages 189 -200
DOI https://doi.org/10.5194/cp-12-189-2016
Publisher URL http://dx.doi.org/10.5194/cp-12-189-2016

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