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相关分析揭示阿尔泰山北部低海拔山地的西伯利亚落叶松树轮年表与帕尔默干旱指数(PDSI)之间存在显著相关。因此,文中利用该树轮年表重建了阿尔泰山北部过去251年来1-8月的PDSI指数变化,方差解释量达43.4%。该PDSI指数重建序列与周边地区PDSI指数的变化趋势比较一致,并能够表征额尔齐斯河径流变化。重建结果揭示了19世纪末期极端干旱阶段和自20世纪末期以来暖湿化的减缓。同时,研究还揭示来自北冰洋水汽和西风强度变化对于研究区干湿变化起着关键性作用。
Correlation analysis revealed a significant correlation between the chronological table of Siberian Larch tree rings and the Palmer Drought Index (PDSI) in the low altitude mountainous area of northern Altay. Therefore, we use this tree-ring chronology to reconstruct the change of PDSI index from January to August in the northern Altay in the past 251 years, and explained the variance of 43.4%. The trend of the PDSI index reconstruction sequence is consistent with that of the surrounding area PDSI index, and it can characterize the runoff change of the Irtysh River. The reconstruction results reveal the slow dry season in the late 19th century and the slowdown of warm-humidification since the late 20th century. At the same time, the study also revealed that the variations of water vapor and westerly intensity from the Arctic Ocean play a key role in the variation of wet and dry areas in the study area.