【摘要】 应用方差分析、经验正交函数、合成分析 ,研究了天目山柳杉 (Cryptomeriafortunei)树轮中δ13C随方位的分布特征。应用相关分析探讨了这种分布特征的年际差异与环境因素的关系。结果表明 :树轮δ13C值有显著方位差异和年际变化 ,不同方位的差异可以用 4个基本角分布型表示 ,其中一型表示各方位δ13C比多年平均值偏大 ,其中北 (N)、西 (W)、西南 (SW)、南 (S)较平均值偏大约 0 .5 ,而其余 4个方位偏大不到 0 .2 ;二型各方位也较多年平均值偏大 ,但各方位差异不大 ,除N方位较小外 ,其余均在 0 .2～ 0 .4之间。三型为各方位δ13C较平均状况偏小 ,其中西北(NW)、东北 (NE)方位约偏小 0 .4,其余方位偏小 0 .2～ 0 .3。四型表现为NE、东 (E)、东南 (SE)与平均状况一致 ,西北(NW )方位较平均状况偏大约 0 .1,N方位偏小 0 .2 ,其余 3个方位则偏小约 0 .3。而其年际变化既可用这 4个角分布型的更替表示 ,也可以用第一、二主成分表示。δ13C的第一主成分与前一年 8～ 12月降水量负相关 ,与当年 1～ 3月降水正相关。第二主成分与前一年 8月至当年 1月的 6个月平均气温正相关。不同的角分布型与不同的气候状态相联系。一型出现的有利气候条件是 :R8～ 12 少、R1～ 3 多、T3～ 7低并且T8～ 1高 ;二型出现的有利气候条更多还原

【Abstract】 The characteristics of azimuth distribution of δ 13 C in Cryptomeria fortunei tree rings in Tianmu Mountain regions was studied by means of statistic methods including variance analysis,composition analysis and empirical orthogonal function （EOF） analysis. The effects of environmental factors on the interannual alternation of δ 13 C azimuth distribution patterns were also investigated by correlation analysis. The results showed that δ 13 C in Cryptomeria tree rings varied along with both azimuth and time significantly. The variation along with azimuth can be represented by four basic azimuth distribution types （denoted by Types 1,2,3 and 4）. Type 1 : the δ 13 C anomalies in all azimuths are positive, and they are >0.5 in north （N）, west （W）, southwest （SW） and south （S） and between 0.2₀.4 in the other four directions. Type 2 : also with positive anomalies in all azimuths as in Type 1, but the δ 13 C anomalies are in the interval 0.2₀.4 in most directions except for N （<0.2）. Type 3 : the δ 13 C anomalies are about -0.4 in the NW and NE, and in the range of -0.3 to -0.2 in all other directions. Type 4 : the anomalies in NE, E and SE directions are near 0.0 while at 0.1, in the NW, -0.2 in N, and -0.3 in the other 3 directions. The δ 13 C variation with time can be presented by either the alternation of the four basic types or by the first two principle components （PC1 and PC2） of the eight_azimuth δ 13 C time_series. Furthermore, the PC1 significantly positively correlated with the total precipitation for the period from January to March and negatively correlated with the total rainfall for the period from August to December of the last year. There was a positive correlation between average temperature for the period from August to January along the PC2 axis. The δ 13 C azimuth distribution type varies under different climatic conditions. The favorable environmental factors for types 1 and 2 include: 1) shortage of precipitation from August to December of the preceding year; 2) richness of rainfall from January to March, and 3) lower temperature from March to July and higher （lower） temperature from last August to present January. The opposite climatic conditions were favorable to types 4 and 3. This phenomenon suggests that the δ¹3 C azimuth distribution types may contain environmental information, which could be used to established more detailed historical climate data by both averaged δ 13 C in whole tree ring and its azimuth distribution type time series.更多还原