天山北坡东部地区树轮宽度年表特征分析

通过对天山北坡东部地区8个树轮宽度标准化年表的有关参数的对比,证明苏巴什沟与白杨河沟年表包含有较多的气候信息,8个树轮宽度标准化年表的互相关系数平均值达0.530,其中白杨河沟与苏巴什沟年表的相关系数高达0.725。说明所采样本对该区域的气候具有较好的代表性。再将8个树轮宽度标准化年表与附近的奇台县、木垒县两个气象站1961—2007年逐月降水和平均最低气温,及单月降水和单月气温进行相关分析。结果表明,天山东部地区白杨河沟的树轮宽度生长与上年7月至当年6月的降水呈正相关,其相关系数为0.597,显著性水平达0.000006,与当年6月平均最低气温呈负相关,相关系数为-0.437,显著性水平达0.001,上述均具有明确的树木生理学意义。研究还发现,在0.05显著性水平上,8个年表的树轮宽度指数变化以2~3 a的变化准周期最为多见,苏巴什沟、大东沟及白杨河沟年表以11 a准周期多见。就整个地区而言,天山北坡东部地区8个年表中低频气候信息一般多于高频气候信息。

Analysis of Tree-ring Width Chronology Characteristics from Eastern Area on North Slope of Tianshan Mountains

Comparison of some parameters of the eight tree-ring standardized chronologies from eastern Tianshan Mountains area indicated that the Subashigou and Baiyanghegou tree-ring standardized chronologies have recorded more climatic information. The mean value of correlation coefficients between the eight tree-ring standardized chronologies is 0.530, and the highest (0.725) is between Subashigou and Baiyanghegou. The correlation between tree-ring width index and monthly precipitation, mean lowest temperature, and individual monthly precipitation and temperature of Qitai and Mulei stations showed that there is positive correlation between Baiyanghegou tree-ring width chronology and precipitation from last July to current June (R=0.597, Sig. level=0.000006), and a negative correlation between Baiyanghegou tree-ring width chronology and mean lowest temperature of current June (R=-0.437, Sig. level=0.001). At 0.05 significant level, the periods of 2 to 3 years is the most common in the eight tree-ring width chronologies, the periods of 11 years is clear in chronologies of Subashigou, Dadonggou and Baiyanghegou. Generally, the low frequency information is more than the high frequency information in the eight tree-ring standardized chronologies from eastern Tianshan Mountains area.