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In this study, a 177-year April–June Palmer Drought Severity Index (PDSI) for the southern slopes of the Altay Mountains (China) was reconstructed based on the earlywood width of 96 Siberian spruce (Picea obovata Ledeb.) samples located at eight different sites. The reconstructed PDSI tracked the observed data well (r = 0.723, p <.0001, n = 52). This PDSI reconstruction captures some drought years and periods noted in historical documents, and it agrees well with other hydroclimatic reconstructions for the surrounding area. The 22-, 11-, 2.3-, and 2.1-year cycles of the reconstruction and the spatial correlation with sea surface temperature revealed that the variability of the PDSI for the study area might be influenced by both the Schwabe cycle of solar activity and the interannual oscillation of land–atmosphere–ocean circulation systems. Spatial correlation also showed the reconstruction contained climatic signals, being representative of a larger area extending from northern Xinjiang to northeastern Kazakhstan and a part of southern Russia. Synoptic climatology analysis revealed a relationship between anomalous atmospheric circulation and wet/dry years on the southern slopes of the Altay Mountains in China and its surrounding area. [ABSTRACT FROM AUTHOR]

The northern Tibetan Plateau has been subject to recent warming far above the global average. With few instrumental climate records available for this region before the 1950s, paleoclimatic reconstructions must be used to understand annual-to-centennial-scale climate variations and local climate response to large-scale forcing mechanisms. We developed a maximum latewood density chronology of Qinghai spruce (Picea crassifolia) from the southern slope of the Qilian Mountains, northern Tibetan Plateau. Based on the chronology, we reconstructed August–September temperature for 1780–2008. The temperature reconstruction model accounts for 39.7% of instrumental temperature variance from 1957 to 2008, successfully capturing the most recent warming. Superposed epoch analysis indicated a volcanic forcing for temperature, resulting in pulses of cooler conditions that can persist for 2–4 years. Tree-ring data indicated that warm-dry and cold-wet climate combinations mainly occurred in northern Tibetan Plateau before CE 1900, and revealed a clear wetting and warming trend since the 1980s. Our study provides long-term perspective on recent climate change in northern Tibetan Plateau to guide expectations of future climate variability and aid sustainable development, and provides scenarios for climate change adaptation and inputs for climate models representing a broader range of conditions than those of historical climate records. [ABSTRACT FROM PUBLISHER]