根据采自福建沙县萝卜岩保护区的树轮样本,建立了一个长度为207年的树轮宽度标准化年表。通过相关分析发现,树轮宽度标准化年表序列与夏秋干旱季节温度存在显著的负相关。同时,还发现树轮宽度标准化年表序列与夏季亚洲-太平洋涛动指数(IAPO)具有良好的相关性,相关系数为0.60(p〈0.01),这种关系实质上指示了夏秋干旱季节,气旋降水和高温对树木生长的影响。利用树轮宽度标准化年表可较好地重建夏季IAPO,重建值对实测值的解释方差为42.70%,F=13.66。交叉检验表明重建结果是稳定可靠的。夏季IAPO重建序列具有102年、13.0年、9.8年、5.1年、2.9年、2.6年、2.3年、2.2年、2.0年的周期变化,与影响福建地区的较大尺度气候环流周期变化具有良好的一致性。通过对比分析,发现本研究所重建的夏季,。序列与另一夏季IAPO重建序列具有良好的同步性。
So far there are many dendroclimatogical studies being carried out in the northwestern China and Tibetan Plateau. Most tree-ring studies were carried out in environmentally sensitive regions of China and focused on the reconstruction of precipitation and temperature. However, it is important to develop new tree-ring chronologies in tropical and subtropical areas of China, in order to recognize climatic variation in the southeastern China. The site (26°26'N, 117°35'E, site code LBY)is located in Sha County, Fujian. To minimize non-climatic effects on tree growth,only trees with no injury and disease were sampled. Twenty trees were studied. One 5mm core and two 12mm cores were taken from each tree with increment borers. In total 20 cores(5mm)and 30 cores(12mm) were collected. The sampling sites were at 420 -450m elevation a. s. 1. ; on northern slopes with an inclination of 5° -10°. Tree-ring samples were prepared, cross-dated and measured following conventional procedures. Application of the regional curve standardization method (RCS)for tree-ring detrending allowed the preservation of inter-annual to multi-centennial scale variability. The variance in chronologies was stabilized in the chronology compilation process with the Briffa RBAR-weighted method,which uses average correlations between series in combination with sample size each year to make adjustments in the variance for changes in sample size. The expressed population signal (EPS) was used, which represents the degree to which a particular sampling portrays a hypothetically perfect chronology,as a guide in evaluating chronology reliability. An EPS value of 0. 80 is a widely accepted threshold for adequate sample size in chronology development. The calculation shows that the tree-ring width standard (STD)chronology is significantly correlated with the Asian Pacific Oscillation( IAPO )from June to August( r = 0.60, P〈0.01, N = 61 ). Tree-ring data have been used to reconstruct the summer(from June to August)A