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

摘要

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. (C) 2014 Elsevier Ltd and INQUA. All rights reserved.