【作者】 张芳芳；

【导师】 郑永宏；

【作者基本信息】 武汉大学 ， 自然地理学， 2018， 硕士

【摘要】 利用树轮稳定同位素序列来反映和记录过去气候变化具有重要的理论和实际意义。本文利用采自湖北神农架地区的18株巴山冷杉23根树轮样芯,经过一系列实验室处理,最终研制出神农架地区巴山冷杉年分辨率的1790-2011年的树轮δ¹⁸O、δD序列,并分析了树轮δ¹⁸O、δD序列与其立地环境的气候因子、大气环流指数和海温之间的相关响应,进一步讨论了上述这些气候因子、环流因子以及海温影响树轮δ¹⁸O、δD序列的作用机理和影响程度,以期扎实树轮同位素研究气候变化的理论基础,从而实现利用树轮δ180、δD序列重建过去海温变化。为了分析神农架地区树轮氢氧同位素序列的气候指示意义,我们将该地区树轮δ¹⁸O、δD序列和邻近的巴东气象站记录的气候数据进行了相关性分析,探讨了树轮δ¹⁸O、δD序列对气候要素响应的敏感程度。响应结果表明,神农架地区树轮δ180序列主要对当年6-7月降水量、当年3-4月气温和当年7月相对湿度响应敏感,在一定程度上记录了 6-7月降水量、3-4月气温和7月相对湿度的变化,由此可以看出该地区气候要素变化与树轮δ¹⁸O的变化密切相关;神农架地区树轮δD序列与降水、气温、相对湿度和日照时数的相关性均较低,未达到显著性水平,因此树轮δD序列对降水、气温、相对湿度和日照时数的的响应均不敏感。为了分析树轮δ¹⁸O、δD序列与区域大气环流之间的相关关系,我们利用神农架地区树轮δ¹⁸O、δD序列与区域大气环流指数进行相关分析,探讨了树轮δ¹⁸O、δD序列与北半球副高面积指数（5E-360）、南海副高面积（100E-120E）、太平洋极涡面积指数（Zone 2,150E-120W）、南海海温（SST）及南方涛动指数（SOI）之间的相关程度。相关结果表明,树轮δ¹⁸O序列与当年2-3月北半球副高面积指数（5E-360）、9月南海副高面积（100E-120E）、1月太平洋极涡面积指数（Zone 2,150E-120W）及当年1月南方涛动指数（SOI）之间有密切关系,这表明神农架地区树轮δ180序列在很大程度上记录了较多的区域大气环流信息;树轮δD序列与与当年7月北半球副高面积指数、9月南海副高面积以及8月太平洋极涡面积指数呈显著相关。我们还发现神农架地区树轮δ180序列与4-5月南海海温（SSST）呈显著正相关,说明4-5月南海海温对神农架树轮δ180值具有重要影响;神农架地区树轮δD序列与5月南海海温呈显著正相关,与1月孟加拉湾海温呈显著正相关,且达到了重建水平,因此重建了孟加拉湾地区1月海温。为了研究神农架树轮δ¹⁸O序列的变化幅度和周期,对树轮δ¹⁸O、δD序列进行了滑动平均和功率谱分析,发现树轮δ¹⁸O序列具有两个明显周期,分别为7.8a和23.3a,7.8a周期可能与南海海温有关,23.3a周期可能与太阳黑子活动有关。树轮δD序列也具有两个明显周期,分别为2a和3.6a,这两个周期可能与厄尔尼诺现象有关。更多还原

【Abstract】 It is of great theoretical and practical significance to use tree-rings stable isotope choronologies to reflect and record past climate changes.In this paper,23 cores of 18 Abies fargesii trees were collected from the Mt.Shennongjia of Hubei Province.Through a series of laboratory treatments,we finally developed annual resolution the tree-ring δ¹⁸O and 8D choronologies from 1790 to 2011 of the Abies fargesii at the Mt.Shennongjia.Then we ananlysis the correlations between tree-ring δ¹⁸O and δD choronologies and the climatic factors of the site environment,atmospheric circulation indices and SST.We further discuss that those climatic factors,circulation factors,and the SST action mechanism and influences on the δ¹⁸O and δD value of tree rings in order to provide a theoretical basis for the study of past climate change of tree ring isotope,so as to use the δ¹⁸O and δD chronologies of tree rings to reconstruct the past climate change.In order to analyze the climatic indication significance of δ¹⁸O、δD value of tree-ring in the Mt.Shennongjia,we perform correlation analysis between the δ¹⁸O and δD chronologies of tree rings and data of the approaching Badong meteorological stations,and discuss the response sensitivity of the δ¹⁸O and 8D chronologies of tree rings to the climatic factors.The response results show that the δ¹⁸O and δD chronologies of tree rings in the Mt.Shennongjia is mainly response sensitive to the June-July precipitation,the March-April temperature and the July relative humidity.The changes of the June-July precipitation,the March-April temperature and the July relative humidity are recorded to a certain extent in the δ¹⁸O and δD chronologies of tree rings.Then we can see that the δ¹⁸O and δD chronologies of tree rings and changes of climate factors in the study area have a close connection.The correlation between the δ¹⁸O and δD chronologies of tree rings and the precipitation,temperature,relative humidity and sunshine hours in the Mt.Shennongjia is lower,even it does not reach a significant level.Therefore,the response of the δ¹⁸O and δD chronologies of tree rings to precipitation,temperature,relative humidity and sunshine hours is not sensitive.In order to analyze the correlation between the δ¹⁸O and δD chronologies of tree rings and regional atmospheric circulation,we perform correlation analysis between the δ¹⁸O and δD chronologies of tree rings in the Mt.Shennongjia and regional atmospheric circulation indices.We discuss the response sensitivity of the δ¹⁸O and δD chronologies of tree rings to the Area Index of Northern Hemisphere Subtropical High（5E-360）,the Area Index of South China Sea Subtropical High（100E-120E）,the Polar Vortex Index of Pacific Ocean（Zone 2,150E-120W）,and the Southern Oscillation Index（SOI）.The results show that the δ¹⁸O chronologies of tree rings and the February-March Area Index of Northern Hemisphere Subtropical High（5E-360）,the September Area Index of South China Sea Subtropical High（100E-120E）,the January Polar Vortex Area Index of Pacific Ocean（Zone 2,150E-120W）and the January Southern Oscillation Index（SOI）have a close relationship.These indicate that the tree-ring δ¹⁸O chronology records a large scale of atmospheric circulation information.There is significant correlation between the δD chronologies of tree rings and the July Area Index ofNorthern Hemisphere Subtropical High（5E-360）,the September Area Index of South China Sea Subtropical High（100E-120E）,the August Polar Vortex Area Index of Pacific Ocean（Zone 2,150E-120W）.We also found that there is a significant positive correlation between the δ¹⁸O chronology of tree rings and the April-May SST of the South China Sea,suggesting that the April-May SST in the South China Sea has an important influence on the δ¹⁸O value of the tree ring in the Mt.Shennongjia.The relationship between the δD chronology of tree rings and the May the SST in the South China Sea,the January SST in the Bay of Bengal are a significant positive correlation.The correlation coefficient between the 8D chronology of tree rings and the January SST in the Bay of Bengal reached the reconstruction level,so as to we reconstruct the January SST in the Bay of Bengal.In order to study the variation amplitude and periodicity of the δ¹⁸O and δD chronologies of tree rings,the 5180 and δD chronologies of tree rings were analyzed by means of moving average and power spectrum.It is found that the δ¹⁸O chronology of tree rings has two distinct periods of 7.8a and 23.3a.The 7.8a period may be related to SST in the South China Sea,and the 23.3a cycle may be related to sunspot activity.The the δD chronology of tree rings also has two distinct periods,2a and 3.6a,which may be related to the El Nino phenomenon.更多还原