May-june mean temperature reconstruction over the past 300 years based on tree rings in the Qilian Mountains of the northeastern Tibetan Plateau

Abstract

A juniper (Juniperus przewalskii Kom.; synonym: Sabina przewalskii) tree-ring width chronology was developed to investigate the regional climate variability for the Qilian Mountains. Statistically, the chronology was appropriate for reconstructing the regional mean temperature of May-June from A.D.1700 to the present. The phenomenon of synchronous extremely high temperatures and extreme droughts in the 1920s was revealed by comparing our reconstruction with drought events in this region. Multi-taper spectral analysis indicated the existence of significant low- and high-frequency periods (40-46 years, 34,23-25,5.6, 2.1,2.5-2.8 years). Overall, the study not only extended the temperature record, but also provided reliable long-term temperature information to help understand the possible forcing of climate changes in the Qilian Mountains.