中文摘要：

利用树轮宽度年表重建了东天山木垒地区自公元1727年来上年8月至当年6月降水量,调整自由度后的方差解释量为36％（1962～2007年）.过去281年来,木垒地区降水量变化存在5个偏干阶段（1742～1777年、1808～1832年、1853～1876年、1908～1934年和1975～ 1992年）和4个偏湿阶段（1778～ 1807年、1833～ 1852年、1877～1907年和1935～1974年）.与代表大范围降水变化的重建序列对比表明,该降水量重建序列与北疆降水变化的3个偏湿期（1778～ 1807年、1833～1852年和1935～1974年）和2个偏干期（1808～1832年、1853～1876年）存在一致.功率谱分析显示该重建序列存在14.3年、10.9年的显著准周期（p＜0.05）.相关分析结果显示,该重建序列代表了东天山区域局地降水量变化情况,且与邻近的中天山巩乃斯地区降水变化最为相似.随着空间距离的加大,该重建序列与自东北向西南方向上天山不同区域降水变化的相关性逐渐减弱.

英文摘要：

In this study, a total of 99 cores from 54 spruce trees （Picea schrenkiana） were obtained for two sites, named as Subashigou （ SBG in 43°35.65′N, 90′12.24′E and 2491m a.s.l.） and Baiyanghegou （BYX in 43°36.92′N, 90°27.75′E and 2285m a.s.l.） in the Mulei region in the eastern Tien Shan Mountains in September 2007. All the tree-ring cores were naturally dried, mounted, surfaced, and cross-dated following standard dendrochronological procedures. Each ring-width was measured with a resolution of 0.001mm by a dendrometer （ Velmex Measuring System）. The quality control of the cross-dating was carried out using the COFECHA program. The ARSTAN program was used for de-trending and developing tree-ring chronologies. The age-and size-related variation of the tree-ring widths was removed by a single detrending process applied on each tree-ring measurement： an 100-year cubic smoothing spline. After all these processes, three kinds of chronologies from one sample site were obtained： standard chronology, residual chronology, and Arstan chronology. For further analysis, we used the standard chronologies that contain the common variations among the individual tree-core series and retain a low-through highfrequency common variance, presumably in response to climate. Due to the short distance, the similar natural enviroment, and the high correlation between two singal chronologies, all the raw tree-ring-width data from two sampling sites （SBG and BYX） to develop a longer and better-replicated regional ring-width composite chronology （ETS）. August-June precipitation has been reconstructed back to 1727A.D. for the Mulei region in the eastern Tien Shan Mountains, using the ETS chronology. The reconstruction explains 36% of the variation in the observed precipitation from 1962 to 2007. Some extremely climatic events in the historical documents are captured precisely in this new reconstruction. Dry periods occurred during the periods of 1742 - 1777, 1808- 1832, 1853 - 1876, 1908-1934, and 1975-