【作者】 赵兴云；

【导师】 王建； 钱君龙；

【作者基本信息】 南京师范大学 ， 自然地理学， 2006， 博士

【摘要】 由于树木年轮具有定年准确、连续性好、分辨率高、对环境变化敏感性强等优势，已在全球气候变化研究中被广泛应用。在我国西部及北部干旱地区，已有学者利用树木年轮对气候变化进行了较多研究，而东部地区，尤其是热带、亚热带暖湿地区的研究相对薄弱。本文以地处我国东部亚热带地区的浙江大目山、江西庐山和南京紫金山为研究区域，以树轮δ¹³C作为研究手段，分析了树木年轮δ¹³C年序列变化特点及其环境意义；论证了树轮δ¹³C方位变化存在的普遍性与稳定性，分析了树轮δ¹³C方位变化的特点、极值的时空迁移规律；探讨了树轮δ¹³C随方位变化的机理。主要研究内容与结果为： 1．对天目山三株柳杉树轮δ¹³C年序列进行了相关分析，结果表明：三株树轮δ¹³C序列含有相似的高频与低频变化，气候因素与大气因素对不同柳杉个体δ¹³C年序列高、低频变化的影响是共同的。三个δ¹³C序列间也存在差异，但其个性差异对其共性变化影响较小，个性差异并不影响树轮δ¹³C作为气候变化研究代用资料的适宜性与重建历史气候结果的可靠性与一致性。 2．在对树轮δ¹³C序列的高频变化与气候要素相关检验的基础上，通过逐步回归法求得了树轮△δ¹³C与气候要素间的最佳多元回归方程，回归方程的复相关系数0.703，方差解释量达到49.2％。回归结果表明，该区树轮δ¹³C值受多个气候变量的综合影响。 3．通过建立信息转换函数重建了天目山地区1685年以来3～9月降水量及年平均气温。分析与检验表明：重建结果较好地反映了该区300年的气候变化历史。300年的气候冷、暖变化与我国近500年的气候变化及我国东部地区其它地质记录所反映的区域气候变化有较好对应。重建结果证明了小冰期信息在天目山树轮δ¹³C中存在的可信性。史料所记载的一些大寒年、大涝年及大旱年在重建序列中得到较好印证。重建序列中含有58.82a、21.28a、13.70a、3.23a、2.63a、2.33a和2.07a的准周期振荡。表明该区树轮δ¹³C组成序列对太阳活动与ENSO事件等有较好记录。 4．用三个树轮δ¹³C序列重建了该区过去大气CO₂浓度变化，重建结果很好的反映了300年大气CO₂浓度的长期变化趋势，三个δ¹³C序列重建大气CO₂浓度结果的一致性证明，用同一地区不同树木个体的δ¹³C序列可以重建出基本一致的大气CO₂浓度的历史变化。 5．利用三株树轮δ¹³C序列研究了树木生长对水分状况的响应，结果表明三株树木所反映的水分利用率均是增加的，且增长变化趋势基本一致，1835年后均呈现出明显增长。 6．进一步验证了树轮δ¹³C方位变化存在的稳定性，分析了树轮δ¹³C极值时空迁移变化，结果表明树轮δ¹³C极值并不固定出现在某些方位，而是随树木生长坡向及时间发生方位转移及年际漂移。 7．对树轮δ¹³C年序列间的差异及方位变化机理进行了探讨。不同坡向上树木受光强度与温度差异以及树冠周围受光时间的差异是导致树轮δ¹³C年序列差异及方位变化的主要因素。 8．树轮不同方位的△δ¹³序列对气候信息的记录能力及强度存在差异，采用同归分析法，对各个△δ¹³C序列记录的气候信息进行较好的重建，且重建精度及效果较好。更多还原

【Abstract】 The tree ring has been used widely in the field of global climate change due to its advantage of accurate for cross-dating, well continuity, high-resolution and high sensitivity to the environment. Some academicians have already studied the climate change in the dry area of west and north China by using tree rings. The similar study is relatively lacking in east China especially in the tropic and subtropics region with warm and wet character. Taking Tianmu Mountain, Lushan and Chongshan as the area of case study, we measure the tree ring annual series of δ¹³C and azimuth distribution sampled from these areas by using the tree ring δ¹³C as researching index. We analyze the character of the tree ring annual series of δ¹³C and azimuth distribution and set forth its environmental significance. Moreover, we demonstrate the universality and stability of the existence of azimuth variation of tree ring δ¹³C and analyze the azimuth variation character of δ¹³C and the space and time transferring discipline of extremum, further, probe the mechanism of tree ring δ¹³C changing along with azimuth. The main process and conclusions are as follows:We analyze the correlation of the δ¹³C annual series of the Cryptomeria fortunei（CF） collecting from Tianmu Mountain. The result indicates that there is the similar variation of high frequency and low frequency among the three δ¹³C series and both the factor of climate and factor of atmosphere have influenced together on this variation of CF individuals. There are some differences among the three δ¹³C series, but the individual difference has little influence on the commonness. The individual difference does not make impact on the feasibility of using the δ¹³C as substitutive index on studying climatic changes as well as the reliability and consistency of reconstructing result of historical climate.Based on the correlation test between high-frequency change and climate factor of the tree ring δ¹³C series, we attain the best multivariate regression equation of the δ¹³C and climate factor by using stepwise regression. The correlation coefficient is 0.703 and the explanation rate of variance is 49.4%. Generally, the result shows that the tree ring δ¹³C is restricted by several climatic variable in this area.Through constructing transfer function of information, we reconstruct the history of precipitation from Mar to Sep and the annual mean temperature since 1685 of Tianmu Mountain. The analysis and test illustrate that the result of reconstructing reflects preferably the historical climate variation during the past 300 years in this area. The climatic variation during the 300 years in this area has close correspondence with the climatic variation during the past 500 years of our country and the territorial climate variation reflected by the other geological records in the east region of China. The result proves that the creditability of information of the Little Ice Age existing in the record of tree ring δ¹³C series of Tianmu Mountain.Some important colder, wetter and drier periods recorded in historical materials were confirmed by the reconstructing series. The quasi-periodic oscillations of 58.82 a, 21.28 a, 13.70 a, 3.23 a, 2.63 a, 2.33 a and 2.07 a are involved in the reconstructing series, which show that it has a reasonable record for sunspot and ENSO in the tree ring δ¹³C series of this area.The result reconstructing the change of atmospheric CO₂ concentration in virtue of the three δ¹³C series reflects the long-time changing trend of atmospheric CO₂ concentration during the past 300 years favorably. The conclusion which is educed by the coherence of reconstructing atmospheric CO₂更多还原