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Swiss tree rings reveal warm and wet summers during medieval times
Author(s) -
Kress Anne,
Hangartner Sarah,
Bugmann Harald,
Büntgen Ulf,
Frank David C.,
Leuenberger Markus,
Siegwolf Rolf T.W.,
Saurer Matthias
Publication year - 2014
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1002/2013gl059081
Subject(s) - precipitation , climatology , larch , anomaly (physics) , environmental science , forcing (mathematics) , radiative forcing , atmospheric sciences , climate change , geology , oceanography , geography , ecology , meteorology , biology , condensed matter physics , physics
We present a 1200 year drought reconstruction for the European Alpine region based on carbon isotope variations of tree rings from living larch trees and historic timber. The carbon isotope fractionation at the study site is sensitive to summer precipitation, temperature, and irradiance, resulting in a stable and high correlation with a drought index for interannual to decadal frequencies and possibly beyond ( r 2 = 0.58 for 1901–2004, July/August). When combining this information with maximum latewood density‐derived summer temperature, a strongly reduced occurrence of summer droughts during the warm A.D. 900–1200 period is evident, coinciding with the Medieval Climate Anomaly (MCA), with a shift to colder and drier conditions for the subsequent centuries. The warm‐wet MCA contrasts strongly with the climate of the drought‐prone warm phase of the recent decades, indicating different forcing mechanism for these two warm periods and pointing to beneficial conditions for agriculture and human well‐being during the MCA in this region.