神农架地区树轮δ^(18)O序列的气候指示意义

Climatic significance of tree-ring δ^(18)O in Shennongjia Mountain

通过对湖北省神农架巴山冷杉(Abies forrestii)树轮纤维素氧同位素的分析,建立了1790-2011时段的年分辨率的δ^(18)O年表。将树轮δ^(18)O序列与邻近的巴东气象站记录的气候数据、大气环流数据以及南海海温进行对比分析,研究了树轮δ^(18)O序列对气候要素的响应。结果表明,神农架地区树轮δ^(18)O序列与该地区气候要素密切相关:与当年6-7月降水量呈负相关、与当年3-4月温度呈正相关,与当年6-7月相对湿度呈负相关。同时,树轮δ^(18)O序列与当年2-3月北半球副高面积指数(5E-360)、9月南海副高面积指数(100E-120E)、1月太平洋极涡面积指数(Zone2,150E-120W)及4-5月南海海温(SST)呈显著正相关;与当年1月南方涛动指数(SOI)呈负相关。表明树轮δ^(18)O序列在一定程度上记录了大尺度的大气环流信息。该研究有助于进一步认知神农架地区树轮稳定氧同位素在过去气候变化研究中的潜在价值,为进一步气候重建研究提供科学依据。

In this study, a stable oxygen isotope chronology from tree-ring cellulose（δ18O in Bashan fir（Abies forrestii） from Mt. Shennongjia in Hubei Province was correlated with meteorology records of the Badong meteorological station, circulation index data, and sea surface temperature of the South China Sea（SST）. The chronology spans the time period of 1790-2011. The results indicate that the tree-ring δ18Ochronology is closely correlated with local climate factors. The tree-ring δ18Ochronology has a significantly positive correlation with March to April monthly mean temperature, has a significantly negative correlation with June to July monthly mean precipitation and June to July monthly mean relative humidity. Meanwhile, the tree-ring δ18Ochronology has a significantly positive correlation with February to March area index of the northern hemisphere subtropical high（5 E-360）, September area index of the South China Sea subtropical high（100 E-120 E）, January polar vortex area index of the Pacific Ocean（Zone 2, 150 E-120 W）, and April to May sea surface temperature of the South China Sea（SST）. A significantly negative correlation was found between the tree-ring δ18Ochronology and January southern oscillation index（SOI）. These indicate that the tree-ring δ18Ochronology records at a large scale of atmospheric circulation information.This study is helpful to further understand the potential value of tree ring stable oxygen isotopes in the past climate change studies in Mt.Shennongjia, and provide a scientific basis for further research on climate reconstruction.