中文摘要：

通过对新疆伊犁尼勒克地区3个采点的雪岭云杉树轮宽度标准化年表与尼勒克气象站月降水的单相关普查发现,树轮宽度标准化年表与上年7—8月降水呈显著正相关,且具有明确的树木生理学意义.将树轮宽度标准化年表进行平均得到区域树轮宽度年表,再考虑到上年7—8降水对当年、次年及再次年树木年轮生长的影响,建立区域年表对上年7—8降水的重建方程,重建了1671—2006年336a来的7—8月降水序列,经多方面验证,重建结果是可信的.336a来,尼勒克地区7—8月降水经历了6个偏干阶段和7个偏湿阶段,其中偏湿年数多于偏干年数;最干旱年份为1713年,7—8月降水比多年均值偏少69.4%;最湿润年份为1783年,7—8月降水比多年均值偏多63.5%;7—8月降水长序列变化存在2.0a、2.2a、3.8a、4.9a、9.7a的显著准周期,且在1757年、1852年、1899年前后降水由多向少发生突变,1718年、1778年、1873年前后降水由少向多发生突变,1757年、1778年前后的突变与前人的研究结果相一致.

英文摘要：

Single correlations between the standard chronologies of tree-ring width in three sites and precipitation at the Nilka Weather Station indicated that the correlations were significant among standard chronologies of tree-ring width and precipitation from July and August last year in Nilka,which has distinct physiological significance with a maximum correlation of 0.598（α=0.000006）.Averaging the standardization chronologies of tree-ring width of the three points as the a regional average tree-ring width chronology,and taking into account the impact of July and August precipitation at last year on the tree-ring growth at the current year,the following year and another year,using the regional tree-ring standardized chronology,a 336-year precipitation series was well reconstructed.It was verified that the reconstructed precipitation series was reliable.Analyzing the 336-a reconstructed precipitation series found：1）There were 6 dry phases bellow its mean and 7 wet phases above its mean;and the number of wet-partial years is more than that of the dry-partial years;2） The minimum precipitation occurred in 1713,which was 69.4% less the long-term mean,and the maximum precipitation occurred in 1783,which was 63.5% more than the long-term mean;3）There were significant change of the July and August precipitation with periods of 2.0a,2.2a,3.8a,4.9a,and 9.7a in the reconstructed longterm precipitation series;4）There were six abrupt changes in 1718,1757,1778,1852 and 1873,i.e.,three abrupt changes from high to low in 1757,1852 and 1899 and three abrupt changes from low to high in 1718,1778 and 1873.The abrupt changes in 1757 and 1778 were corresponding to the abrupt changes presented by the previous researches.