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

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    • C. S. M. Turney
    • R. T. Jones
    • C. Fogwell
    • J. Hatton
    • A. N. Williams
    • A. Hogg
    • Z. A. Thomas
    • J. Palmer
    • S. Mooney
    • R. W. Reimer

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    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.

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    DOI

    Original languageEnglish
    Number of pages12
    Pages (from-to)189-200
    JournalClimate of the Past
    Journal publication date03 Feb 2016
    Issue number2
    Volume12
    DOIs
    Publication statusPublished - 03 Feb 2016

    ID: 25576872