TREE-RING RECORDS OF SUMMER TEMPERATURE VARIATION AND HYDROTHERMAL CONFIGURATION MODE ON THE SOUTHERN SLOPE OF ALTAI MOUNTAINS IN THE PAST 304 YEARS

The climate on south slope of the Altay Mountains (China Altay) is affected by the westerlies, the airflow from the Arctic Ocean, the Mongolia-Siberia High and the Asian Low, resulting in unique climate pattern in this region. China Altay is also located in an important place along "the Silk Road Economic Belt" and the Eurasian communication hub, climate change has a significant impact on the surrounding human production, life, and nature ecosystem. Therefore, it is necessary to understand the long-term history of climate change around the China Altay, identifying the characteristics and rules to cope with the possible climate disasters in the future. In this study, using Pearson correlation analysis based on a significant relationship between the tree-ring width chronology from 60 Siberian larch tree-ring cores (latitude: 48.5° N, longitude: 87.18° N, elevation: 2037 m) and the summer temperature (June-July) (r=0.626, n=58, p < 0.001), we established the first order linear regression model equation to reconstruct summer temperature variations of the China Altay during the past 304 years (1715~2018 A.D.). The statistical results showed that the reconstruction was stable and reliable. The spatial correlation with gridded temperature dataset indicates that the reconstruction could represent temperature variations within a wide area. The five warm periods (1740~1767, 1775~1793, 1837~1847, 1898~1909, and 1990~2018) and five cold periods (1715~1727, 1807~1828, 1848~1858, 1876~1897, and 1927~1940) were detected from our reconstruction. Although rapid warming occurs since 1990 (1990~2018, 0.33 ℃ than normal), it has not exceeded the temperature range of 1740~1767 (0.49 ℃ than normal). Combined with the surrounding precipitation reconstruction, we found that the study area showed a synchronized configuration pattern of summer precipitation and temperature during the past three centuries, that is, the warm wet/cold dry mode dominated.