Early summer temperature changes in the southern Altai Mountains of Central Asia during the past 300 years

Abstract

June–July mean temperature was reconstructed back to 1698 for the southern Altai Mountains in eastern Central Asia using four temperature series based on tree-ring widths. The reconstruction explains 48% of the variation in the observed temperature from 1962 to 2003. Warm periods occurred during 1714–1732, 1753–1776, 1800–1840, 1866–1886, 1893–1911, and 1943–1969, while the periods of 1708–1713, 1733–1752, 1777–1799, 1841–1865, 1887–1892, 1912–1942, and 1970–1993 were relatively cold. Power spectral and wavelet analyses demonstrated the existence of significant 50-, 14-, 2.8-, and 2.5-year cycles of variability. The results of a spatial correlation analysis suggested that this temperature reconstruction contains climatic signals for a large area of Central Asia. After employing a 21-year low-pass filter, the coherence of the newly reconstructed series with a regional temperature reconstruction for Central Asia and also with a local temperature reconstruction for the Zajsan Lake area of East Kazakhstan indicates that our temperature reconstruction captures broad-scale regional climatic variations in the low-frequency domain.