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祁连山东部位于亚洲季风西北边缘区,对气候变化十分敏感。由于该区位于半干旱区,降水的变化直接影响人类社会经济的发展,所以研究该区干旱变化情况及其机制非常重要。利用采自祁连山东部西北季风边缘、地处半干旱区的吐鲁沟地区的油松树轮样芯,建立了树轮宽度年表,时间跨度为1866-2003AD。树轮宽度年表与气象因子相关分析结果显示树木生长主要响应生长季内的降水和干旱变化。该年表与附近区域利用树轮宽度重建的帕尔默干旱指数(PDSI)进行对比,结果显示严重的干旱时间发生在1920s-1930s、1966年、1974年、1982年和1990s和21世纪初。多窗谱分析研究表明,该区年表序列存在显著的2~4 a周期(P<0.05),该周期与ENSO变率吻合,与在贺兰山、祁连山其他地区、兴隆山及贵清山研究结果一致,表明这些区域可能受共同气候因子的影响。
The eastern Qilian Mountains are located in the northwestern margin of the Asian monsoon and are very sensitive to climate change. Because the area is located in a semi-arid area, the change of precipitation has a direct impact on the social and economic development of human beings. Therefore, it is very important to study the situation of drought and its mechanism in this area. The tree-ring chronology was established using the oil-pine tree-like cores collected from Tulugou area located in the semi-arid area on the northwest monsoon edge of eastern Qilian Mountains with a time span of 1866-2003AD. The results of tree ring width chronology and meteorological factors showed that tree growth mainly responded to the changes of precipitation and drought during the growing season. The chronology was compared with the Palmer Drought Index (PDSI) using tree-ring width reconstruction in the vicinity, and showed that severe drought events occurred between 1920s-1930s, 1966, 1974, 1982, and the 1990s and early 2000s. Multi-window analysis showed that there was a significant 2 ~ 4-year cycle (P <0.05) in the chronological sequence of this region, which coincided with the ENSO variability and consistent with the results from Helan Mountain and other parts of Qilian Mountains, Xinglong Mountain and Guiqingshan , Indicating that these areas may be affected by the common climate factors.