云南丽江树轮δ^(18)O记录的大气环流变化信息

Atmospheric Circulation Information Recorded in Tree-ring δ^(18)O at Lijiang,Yunnan Province

通过对云南玉龙雪山丽江冷杉年轮晚材纤维素氧同位素(δ18O)的分析,建立了1902-2004时段年分辨率的树轮δ18O序列。将所得序列与相邻的丽江市气象站记录的气候资料对比,分析了树轮δ18O对气候要素的响应。结果表明,丽江冷杉年轮晚材中的δ18O与其生长季气候因子密切相关。主要与季风期(8-10月)的降水和相对湿度、6-10月总云量、5-6月平均温度显著相关,尤其和总云量相关性最高(r=-0.45,P=0.01)。同时,树轮δ18O年际变化与南亚季风指数、东亚夏季风指数呈反相关关系,并与1-5月南方涛动指数负相关显著,在一定程度上反映了大尺度的大气环流影响。

In this paper,tree-ring latewood stable oxygen isotope composition （δ^18O） of Lijiang fir （Abies forrestii） was used to estimate the climatic response of tree-ring δ18O by comparing the δ^18O values with meteorological records from Lijiang meteorological station. The annually resolved tree-ring δ^18O chronology spans the period of 1902-2004. Results indicate that tree-ring δ^18O values of latewood were significantly correlated with climate conditions during the growth season. Tree-ring δ^18O was mainly correlated with precipitation and relative humidity of the wet season in summer （August to October）. Temperature had a weak influence on the tree-ring δ^18O,indicating a relatively high correlation with δ18O in May and June （r = 0.35）,prior to the rainy season. The strongest correlation was found between the total cloud cover and tree-ring δ^18O covering the whole wet season （June to October）. Furthermore,tree-ring δ^18O shows negative and significant correlations with South Asia monsoon index and East Asia monsoon index in different periods. Meanwhile,a strong correlation between tree-ring δ^18O and SOI during the period of 1902-2004,to some degree,indicates that the tree-ring δ^18O recorded a large amount of atmospheric circulation information.