Reconstructed drought variability in southeastern Sweden since the 1650s

Authors

  • Kristina Seftigen,

    Corresponding author
    1. Regional Climate Group, Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden
    • K. Seftigen, Regional Climate Group, Department of Earth Sciences, University of Gothenburg, Box 460, SE-40530 Gothenburg, Sweden. E-mail: kristina.seftigen@gvc.gu.se

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  • Hans W. Linderholm,

    1. Regional Climate Group, Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden
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  • Igor Drobyshev,

    1. Southern Swedish Forest Research Centre, SLU, Alnarp, Sweden
    2. Center for Forest Research and NSERC-UQAT-UQAM Industrial Chair in Sustainable Forest Management, Département des sciences appliquées, Université du Québec en Abitibi-Témiscamingue, Rouyn-Noranda, Canada
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  • Mats Niklasson

    1. Southern Swedish Forest Research Centre, SLU, Alnarp, Sweden
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ABSTRACT

In this study, we present the first regional reconstruction of summer drought for southeastern Sweden. The June–July standardized precipitation index (SPI) was reconstructed over the period 1650–2002 based on Pinus sylvestris L. tree-ring width data, where the reconstruction could account for 41.6% of the total variance in the instrumental record over 1901–2002. Our reconstruction suggests an overall wet 18th century and a dry 19th century. The most outstanding pluvial phase in the pre-instrumental period took place in the mid-1720s and lasted over 50 years, while multi-decadal periods of below average moisture conditions were reconstructed in the 1660s–1720s, 1800s-early 30s, and in the 1840s–50s. Several of these dry spells have previously been found in reconstructions from Sweden and Finland, indicating that our reconstruction reflects large-scale moisture anomalies across eastern Fennoscandia. Comparison of the SPI estimates with mid-tropospheric pressure patterns suggests that summertime drought is associated with positive pressure anomalies over British Isles and the North Sea, while an eastward movement of the Icelandic low-pressure systems over the western part of central Fennoscandia results in wetter than normal June–July conditions over the region of interest.

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