中文摘要：

经验模态分解（Empirical Mode Decomposition,简称EMD）是一种遵循时间序列本身所包含的不同尺度信号特征进行逐级分解,实现时间序列多分辨率分析的有效方法.本文基于EMD方法对采集于祁连山中部的青海云杉树轮宽度序列进行生长量订正,并与传统采用的线性或负指数函数及样条函数拟合法进行多序列订正结果的逐一对比,结合云杉年轮生长的生理特征,分析了EMD方法在云杉宽度生长量订正中的应用潜力.结果表明,通过EMD分解得到的趋势项不仅可以较好地反映树木年轮与年龄相关的生长趋势,还可以克服线性拟合在树木生长受到小生境干扰时因为斜率的适应性变化及方向单一导致的拟合失效及生长量被高估（或被低估）的现象,常用的替代选择样条函数步长的选取又具有一定的经验性和主观性,EMD方法作为一个新的补充,可为线性函数和样条函数不能满足需求时,提供一个新的选择.进一步考察了EMD方法和传统方法获取的两个树轮标准化年表（1845～2000年,EPS＞0.85）与气候因子在器测记录时段（1957～ 2000年）的相关关系,结果显示两者与气象因子的相关结果极为一致,与肃南气象站前年8月至当年7月降水总量呈显著的正相关（r均通过了99％的信度检验）,表明通过EMD方法对祁连山青海云杉生长量订正后得到的树轮宽度年表与传统方法得到的树轮年表反映了一致的气候信息,可用于历史气候变化分析.进一步利用EMD方法将树轮年表序列分解为不同频谱时段（年际、年代际及多年代际尺度）的子序列,其中年际的高频子序列（＜10年尺度）的主要波动发生在20世纪10～20年代,而10～ 30年尺度子序列的低值期（1925～ 1933年）与甘肃境内文献记录的大范围干旱事件极为吻合,30～60年尺度的多年代际变化显示出3次主要的干湿位相交替变化.

英文摘要：

The relationship between climate factors and tree growth are very complex. Traditional standardization methods still face challenges in retaining the climate signal while removing age-related growth trends and non-climatic disturbances. In this paper, we introduce an Empirical Mode Decomposition （EMD） based standardization method to develop the ring-width chronology, which has the advantages of excluding non-climatic disturbances in individual tree-ring series. First, tree-ring measurements were decomposed by the EMD to produce a number of Intrinsic Mode Functions （IMFs） with different physically-meaningful frequency band. Second, the lowest frequency IMF band, mainly representing age-dependent growth trend, was used to calculate tree-ring index divided by the original treering width records. Based on this method, a new tree-ring chronology was developed from 44 Spruce trees （Picea crassifolia Kom.） at Kong-gang-mu （Kgm） Forest of Sunan County of Qinghai Province in the Qilian Mountains, and the elevations ranged from 2620m to 2770m, which covered the period 1723A.D. to 2000A.D. However, the chronology was more reliable before 1845A.D. when the EPS was greater than 0. 85. Compared two ring-width chronologies from EMD method and traditional method, we can found that the EMD method has the significant advantages in extracting the age-dependent growth trend, especially for improving fitting on the early ＂slow-growth＂ and the late ＂flat-growth＂ periods. It is noted that two chronologies exhibited the coincident significant correlation with meteorological factors of Sunan Meteorological Station （38°50′N, 99°37′E ; 2311m a.s. 1.） in observation period （1957 - 2000）, showed the highest correlation coefficient （r = 0.664, p〈0.01 ） with the total precipitation of the year from the previous August to current July, which indicated that the EMD method successfully preserved climatic signals. Although the EMD method appears to offer both practical and conceptual advantages, we emp