Publication Date:
2015-05-19
Description:
Annually-resolved and millennium-long reconstructions of large-scale temperature variability are primarily composed of tree-ring width (TRW) chronologies. Changes in ring width, however, have recently been shown to bias the ratio between low- and high-frequency signals. To overcome limitations in capturing the full spectrum of past temperature variability we present a network of 15 maximum-latewood-density (MXD) chronologies distributed across the Northern Hemisphere extra-tropics. Independent subsets of continental-scale records consistently reveal high MXD before 1580 and after 1910, with below average values between these periods. Reconstructed extra-tropical summer-temperatures not only reflect these long-term trends, but also distinct cooling pulses after large volcanic eruptions. In contrast to TRW-dominated reconstructions, this MXD-based record indicates a delayed onset of the Little Ice Age (LIA) by almost two centuries. The reduced memory inherent in MXD is likely responsible for the rapid recovery from volcanic-induced cooling in the 14 th century and the continuation of warmer temperatures until ~1600.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
