唐古拉冰芯包裹气体氧稳定同位素气候环境指示意义

Climatic and environmental indications of stable oxygen isotopes in enclosed air bubbles in Tanggula ice core

本研究对钻取自青藏高原中部唐古拉冰川190m冰芯上部的99.5m序列进行了多参数指标的分析测试.以常规阴、阳离子的季节性变化、结合冰芯记录的1963年β活化度峰值和中低纬度山地冰川深部冰体定年模型,建立了99.5m冰芯的年代学序列.结合冰芯钻取点的成冰作用过程分析,明确了冰芯包裹气体与同层位冰体间不存在年龄差异,冰体年龄即为冰芯包裹气体年龄.基于此年代学结论和冰芯年代学结果,将冰芯包裹气体氧稳定同位素值(δ^(18 )O_(atm))与大气中δ^(18 )O_(atm)本底值、冰体气泡含量、冰芯氧同位素和全球太阳辐射量进行对比分析,分析揭示了唐古拉冰芯包裹气体δ^(18 )O_(atm)值变化对区域气候环境影响下冰川表面融化强度变化的指示意义,冰川表面融化强度越强,冰芯包裹气体δ^(18 )O_(atm)值越低.

Multiple parameter measurements were carried out on the top 99.5-meter sequence of a 190-meter ice core drilled from Tanggula glacier in Central Tibetan Plateau.Seasonal variations in conventional negative and cationic ions,1963peak of Beta activation,dating model of deep ice for mountain glacier were used to reconstruct the chronological sequence in the 99.5-meter ice core.Analysis of ice formation at the drilling site revealed no age difference between enclosed air bubbles and ice of the same layer.The age of ice was the age of enclosed air bubbles.Chronological results of the ice core were used to compare variations in stable oxygen isotope(δ18 Oatmratio)in enclosed air bubbles in ice core to background value ofδ18 Oatmratio in the atmosphere,air content in ice and global solar radiation.It was found that variation inδ18 Oatmratio in enclosed air bubbles in Tanggula ice core was closely related to changes in melting intensity of glacier surface.The stronger the melting intensity of the glacier surface,the lower the value ofδ18 Oatmratio in air bubbles of the ice core.