关键词: 水热因子, 种源, 稳定碳同位素, 地理变异

Abstract: As the demarcation line between northern and southern China, Qinling Mountains is a hotspot of global climate change investigations. To reveal the precipitation dynamics in Taibai Mountain, the peak of Qinling Mountains in 1852-2012, we used the tree-ring width index of Larix chinensis in Taibai Mountain and the meteorological data in Baoji City and Mei County nearby, to reconstruct the series of total precipitation from previous November to current June in this area during the past 160 years based on the multiple regression method. The results showed that the reconstruction captured 39.6% (R²_adj =0.370, F=15.11,P<0.001) of the observed precipitation variance during the past 160 years. This result was validated by the documented climate disaster events as well as other tree-ring based precipitation reconstructions from the surrounding area. The reconstructed precipitation data were characterized by obvious wet/dry variation and periodic fluctuation. During the past 160 years, the wet periods were in 1875-1885, 1908-1923 and 1983-2002; the main drought periods were in 1857-1867, 1886-1907, 1923-1935 and 1954-1965. Four main cycles of precipitation existed in the study site with periods of 47-54, 17-22, 13 and 3-7 years. Moreover, we found a trend of strengthened major cycles but weakened minor cycles. The climate change in Taibai Mountain was also affected by larger-scale hydroclimate.

Key words: geographic variation, stable carbon isotope, provenance., hydrothermal factor