Standardization is one of the important procedures in dendroclimatology. We used abundant Qilian juniper （Sabina przewalskii Kom.） tree-ring samples from the eastern margin of the Qaidam Basin to develop a new stand...Standardization is one of the important procedures in dendroclimatology. We used abundant Qilian juniper （Sabina przewalskii Kom.） tree-ring samples from the eastern margin of the Qaidam Basin to develop a new standardization method, i.e. total growth curve （TGC）. The samples that contained the complete pith and reached to the growing culmination around the 40th-60th year were used to fit TGC, and the generalized negative exponential function was used to fit the curve. Usually, most cores cannot reach the arboreal pith for some reasons and it is difficult to determine the arboreal cambial age. The empirical model of initial radial growth （IRG） was employed to estimate the number of rings missing from the pith by the same data and IRG model explained 90.9% of the variance. When developing the chronology, the cambial ages of cores that contained the complete pith were regarded as beginning from the first year and others were determined by the numbers of missing and included rings in the core. Standardization was accomplished by dividing each tree-ring series by corresponding TGC. The chronologies developed by TGC can retain more low-frequency variational information and TGC helps to develop more reliable tree-ring width chronology.展开更多
为了探讨强火山喷发与横断山区干旱变化之间的关系,利用国际树轮库(International Tree-Ring Data Bank,ITRDB)资料集成区域年表,重建了横断山区过去1100多年的春季干旱变化序列,并通过时序叠加法分析了强火山喷发对其影响作用。结果表...为了探讨强火山喷发与横断山区干旱变化之间的关系,利用国际树轮库(International Tree-Ring Data Bank,ITRDB)资料集成区域年表,重建了横断山区过去1100多年的春季干旱变化序列,并通过时序叠加法分析了强火山喷发对其影响作用。结果表明:横断山区树木径向生长包含了干旱与火山信号,信号之间关联为强火山喷发后的4年间对该区域造成干旱影响,影响因素包括火山喷发强度、喷发位置纬度等。中纬度强火山喷发造成的影响更为显著,而低、高纬度强火山喷发影响较弱,影响差异的产生与横断山区干季降水形成的大气环流因素有关。展开更多
基金National Natural Science Foundation of China, No.40371118National Natural Science Foundation of China, No.90502009
文摘Standardization is one of the important procedures in dendroclimatology. We used abundant Qilian juniper （Sabina przewalskii Kom.） tree-ring samples from the eastern margin of the Qaidam Basin to develop a new standardization method, i.e. total growth curve （TGC）. The samples that contained the complete pith and reached to the growing culmination around the 40th-60th year were used to fit TGC, and the generalized negative exponential function was used to fit the curve. Usually, most cores cannot reach the arboreal pith for some reasons and it is difficult to determine the arboreal cambial age. The empirical model of initial radial growth （IRG） was employed to estimate the number of rings missing from the pith by the same data and IRG model explained 90.9% of the variance. When developing the chronology, the cambial ages of cores that contained the complete pith were regarded as beginning from the first year and others were determined by the numbers of missing and included rings in the core. Standardization was accomplished by dividing each tree-ring series by corresponding TGC. The chronologies developed by TGC can retain more low-frequency variational information and TGC helps to develop more reliable tree-ring width chronology.
文摘为了探讨强火山喷发与横断山区干旱变化之间的关系,利用国际树轮库(International Tree-Ring Data Bank,ITRDB)资料集成区域年表,重建了横断山区过去1100多年的春季干旱变化序列,并通过时序叠加法分析了强火山喷发对其影响作用。结果表明:横断山区树木径向生长包含了干旱与火山信号,信号之间关联为强火山喷发后的4年间对该区域造成干旱影响,影响因素包括火山喷发强度、喷发位置纬度等。中纬度强火山喷发造成的影响更为显著,而低、高纬度强火山喷发影响较弱,影响差异的产生与横断山区干季降水形成的大气环流因素有关。
