中国祁连山西段青海云杉树轮密度记录的气候信号

树轮气候学是研究过去气候变化的重要手段之一。以往研究表明,树轮密度是生长季温度的重要代用资料。本文建立了祁连山西段青海云杉132～135年的树轮最大密度年表、树轮最小密度年表、树轮晚材平均密度年表和树轮早材平均密度年表,比较了不同密度年表指示的最优气候信号及其季节组合,评估了其作为气候代用资料的潜力与价值。结果表明:树轮晚材平均密度和树轮早材平均密度对于树木生长季气候信号的响应远低于树轮最大密度和树轮最小密度;树轮早材平均密度和树轮最小密度与帕尔默干旱指数有很强的联系,表明树轮早材平均密度和树轮最小密度有成为干旱代用指标的潜力。

Climatic signals recorded by Qinghai spruce tree-ring density in the western part of Qilian Mountains,China

Dendroclimatology is one of the important methods for studying climate changes in the past. Previous studies showed that tree-ring density is an important proxy for temperature in the growing season. In this study, we established 132-135 years chronologies of tree-ring maximum density, the minimum density, the latewood and the earlywood average density of Picea crassifolia at the western Qilian Mountains. We compared the climatic signal and its seasonal best combination of different tree-ring density chronologies, and evaluated their potential values as climate proxies. The responses of tree-ring latewood average density and the earlywood average density to climate signals during the growing season were much lower than that of tree-ring maximum and the minimum den-sity. The tree-ring earlywood average density and the minimum density had a strong relationship with the Palmer drought index, indicating that the earlywood average density and the minimum tree-ring density had the potential as substitute indicators for drought.