Summer mean temperature reconstruction during the past 285 years based on tree-ring in northern Gaoligong Mountains, northwestern Yunnan of China

Abstract

ABSTRACT Historical temperature reconstructions enable us to understand the long-term thermal variation feature of a region. We developed a tree-ring width chronology of the coniferous species Tsuga dumosa (D. Don) Eichler (Himalayan Hemlock) growing in the northern Gaoligong Mountains, northwestern Yunnan province of China. The climate-tree growth relationship analysis indicated that summer mean temperature was the main limiting factor of the radial growth of Himalayan Hemlock. Accordingly, using a linear regression model, we reconstructed the historical summer mean temperature time series spanning A.D. 1720–2005, which could account for 35.56% of the observedtemperature variance. Based on the reconstruction, the most obvious warme periods were identified as 1715–1730s, 1900–1910, 1920–1940 and 1980–2005, while the main cold episodes were 1740s–1750s, 1810s–1830s, 1910s–1920s and 1940s–1970s. Wavelet and correlation analyses indicated the existence of several interannual (2–4 years and 5.5 years) and decadal (8–12years) cycles in the variation of summer mean temperature, which probably related to El Niño-Southern Oscillation (ENSO), Pacific Decadal Oscillation (PDO), and solar activity.