【摘要】 通过在祁连山东部互助地区采集的油松样本,建立标准树轮(STD)年表,重建该地区近188a上年8月到当年6月的降水,解释方差为48.8%。根据重建结果,历史上的湿润时期有1850s—1860s、1930s末—1950s、1970s—1990s以及2000s;干旱时期有1830s—1840s、1900s、1920s,其中1920s的干旱在北方大范围内普遍存在。根据本文重建结果与周围地区降水和PDSI重建比较,发现该地区降水变化与贺兰山地区干湿变化最为相近,尤其是1940s以前,在1940s之后与青海省德令哈和祁连山中西部地区的重建结果更为相似。因此推测,祁连山东部地区在1940s前后受不同的气候类型主导。更多还原

【Abstract】 A tree-ring width chronology was presented based on Pinus tabulaeformis tree-ring samples from the Eastern Qilian Mountains,China,and a precipitation series for previous August to Current June in the Eastern Qilian Mountains during 1821-2008 were reconstructed.The reconstructed precipitation data can explain 48.8% of the actual precipitation variance during the recent 118 years.During the period,persistently wet periods were found in 1850s-1860s,the end of 1930s-1950s,1970s-1990s and 2000s;and persistently drought periods were found in 1830s-1840s,1900s,and 1920s.The drought epoch during 1920s was widespread in northern China.We compared this precipitation reconstruction sequence with the precipitation or PDSI reconstructions data,and found that the precipitation change in Eastern Qilian Mountains was the most similar with precipitation change in the Helan Mountains,especially during the period of 1820s-1940s.And after 1940s,the precipitation change in Eastern Qilian Mountains was more similar with precipitation change in Delingha of QingHai Province and MidWest of Qilian Mountains.So we supposed that the Eastern Qilian Mountains were probably controlled by different climate styles before 1940s and after 1940s.更多还原