Abstract

Our recent study introduces the reconstruction of May-June precipitation based on Picea Shrenkiana tree-ring growth, spanned AD 1892-2015. We used three monthly climatic gridded data parameters of China which covers with a 0.25° spatial resolution over 1952-2012 (temperature mean (°C), total precipitation (kg m^-2s^-1) and total snow-water equivalent (kg m^-2)) interpolated to our sampling site for highlight correlations coefficients. Snow-water equivalent with ring-width gives us a significant positive correlation (approximately in p<0.05 level) in April-May period (0.411) and September (0.263). With precipitation, correlation is higher in May-June period (0.468) which leads us that limiting factor in this area is water, which is felt during the initial growth of the tree. Results of negative correlation in March-October period (-0.478) with mean temperature, suggest that increase of temperature leads to increase of evaporation and water transpiration. Our reconstruction indicated 6 dry decades (1920, 1930, 1970, 1980, 2000, 2010) and five wet decades (1910, 1940, 1950, 1960, 1990). Our reconstruction confirms to global change, which suggest decreasing precipitation from 1991 until now. To represent our reconstruction geographical meaning, we conducted spatial correlation between our May-June precipitation reconstruction, instrumental gridded interpolated May-June precipitation and gridded CRU TS 4.0 May-June precipitation, which significant in Xinjiang Tian Shan Mountains and goes through Mongolia, Kazakhstan, Kyrgyzstan and Tajikistan. In addition, we are running Multi-taper spectral analysis and after getting results try to connect our study to ENSO variability, with highfrequency cycles 6.1-year (99%), 5.1-4.8-year (90%), 2.7-2.9-years (90%).

Keywords: Tree-ring; Picea shrenkiana; Reconstruction; Tian Shan