O2/N2 ratios of occluded air in the GISP2 ice core
O2/N2 ratios of occluded air in the GISP2 ice core
复制标题
GISP2冰芯中吸留空气的O2/N2比率
DOI：
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发表时间：
2008
期刊：
影响因子：
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通讯作者：
M. Bender
中科院分区：
文献类型：
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作者：
M. Suwa;M. Bender
我们提出并讨论了格陵兰峰顶岛GISP2冰芯中空气中O2/N2比值的记录。在这项研究中，我们检查了1994年测量的331个深度的601个样本的结果，以及2006年新测量的46个深度的92个样本的结果。重复效果差的样本、没有重复的样本以及与每个δO2/N2数据集的平均值相差超过三个标准差的样本被排除在分析之外。大多数复制不良的样品来自与气泡中的气体和以笼形水合物形式存在的气体之间的过渡有关的深度区。我们发现，样品的O2/N2比在- 35°C的11年储存期间平均减少了7.3‰。在不同时间测量的O2/N2比在储存期间进行了损耗校正，并合并形成一个单一的数据集。堆积的GISP2 δO2/N2记录在轨道频率处表现出较强的谱功率，δO2/N2与当地夏季日照呈反相。这一观察结果与早先对东南极洲沃斯托克和圆顶富士冰芯的发现是一致的。它验证了先前的结论，即气泡关闭过程中的分馏取决于太阳照射在表面设置的冰粒性质。此外，GISP2 δO2/N2记录显示了与当地快速气候变化的温度记录相一致的千年期信号。当地夏季日照引起δO2/N2轨道变化的确切机制，以及温度（或相关性质）引起δO2/N2高频信号的确切机制仍有待确定。
[1] We present and discuss the record of O2/N2 ratios in air occluded in the GISP2 ice core retrieved from Summit, Greenland. In this study, we examine results for 601 samples from 331 depths measured by 1994, and 92 samples from 46 depths newly measured in 2006. Poorly replicated samples, samples with no replicates and samples falling more than three standard deviations from the mean of each δO2/N2 data set are excluded from the analysis. The majority of poorly replicated samples are from the depth zone associated with the transition between gas in bubbles and gas present as clathrate hydrates. We found that the O2/N2 ratio of samples is depleted by an average value of 7.3‰ during 11 years of storage at −35°C O2/N2 ratios measured at various times were corrected for depletion during storage and combined to form a single data set. The stacked GISP2 δO2/N2 record shows strong spectral power at the orbital frequencies, and δO2/N2 is in antiphase with local summer insolation. This observation is consistent with the earlier findings for the Vostok and Dome Fuji ice cores from East Antarctica. It validates previous conclusions that fractionation during bubble close-off depends on ice grain properties set at the surface by solar insolation. In addition, the GISP2 δO2/N2 record shows millennial duration signals that are in phase with the local temperature record of rapid climate change. The exact mechanisms by which local summer insolation induces orbital variability in δO2/N2, and by which temperature (or related properties) induce high frequency signals in δO2/N2, remain to be identified.