Gas measurements (N2, O2, Ar, CO2, CH4) of Camp Century and GRIP debris-rich ice.

Ice cores from Camp Century (77° 10' N; 61° 08' W) and GRIP (72° 34’N; 37° 37’W) were sampled and the Niels Bohr Institute in 2021 and 2023. Measurements of gas composition (N2, O2, Ar, CO2, CH4) were performed on 72 samples at the Université Libre de Bruxelles (Brussels, Belgium) using a custom-made system using a Thermo Scientific™ TRACE™ 1310 Gas Chromatograph. The system measured N2, O2 and Ar with a thermal conductivity detector and CO2 and CH4 with a flame ionization detector. Gas extraction was done under vaccum with melting/refreezing.A measurement of gas species in a sample (nmeasured) was corrected for the blank (nblank), the correction factor (CF), and the analytical bias (AB) as follows: ncorrected = (nmeasured - nblank) / (CF * AB) For O2, Ar and CH4, the blanks were under the limit of detection (LOD) and were, therefore, not considered in the correction. The N2 and CO2 blanks were 4.10× 10-7 ± 3.36 × 10-7 and 1.02 × 10-8 ± 1.14 10-8 mol. The CF is estimated as 0.81 ± 0.03 or 0.72 ± 0.01, depending on the line configuration. The AB is 1.06 ± 0.03, 1.06 ± 0.03, 1.05 ± 0.03, 0.86 ± 0.06 and 1.10 ± 0.04 for N2, O2, Ar, CO2, and CH4 , respectively. Uncertainties were propagated using standard error-propagation formulas, explicitly accounting for the covariance between dependent variables.See Ardoin et al. (submitted at The Cryosphere) for the complete method.2021年与2023年，研究团队于尼尔斯·玻尔研究所（Niels Bohr Institute）完成了世纪营地（Camp Century，77°10' N；61°08' W）与GRIP（72°34’N；37°37’W）两处冰芯的采样工作。 随后，研究团队于比利时布鲁塞尔自由大学（Université Libre de Bruxelles, Brussels, Belgium）使用定制化分析系统，搭配赛默飞世尔科技（Thermo Scientific™）TRACE™ 1310气相色谱仪（Gas Chromatograph），对72份样品的气体组分（氮气N₂、氧气O₂、氩气Ar、二氧化碳CO₂、甲烷CH₄）开展了检测。 该系统采用热导检测器（thermal conductivity detector）测定N₂、O₂与Ar的含量，采用火焰离子化检测器（flame ionization detector）测定CO₂与CH₄的含量。 气体萃取流程在真空环境下通过熔融-再冷冻法完成。 样品中气体组分的实测值（n_measured）需通过本底值（blank，n_blank）、校正因子（correction factor，CF）与分析偏差（analytical bias，AB）进行校正，校正公式如下： n_corrected = (n_measured - n_blank) / (CF × AB) 对于O₂、Ar与CH₄，其本底值低于检出限（Limit of Detection，LOD），因此无需纳入校正流程。N₂与CO₂的本底值分别为4.10×10⁻⁷ ± 3.36×10⁻⁷ mol与1.02×10⁻⁸ ± 1.14×10⁻⁸ mol。校正因子CF根据管路配置不同，取值为0.81 ± 0.03或0.72 ± 0.01。针对N₂、O₂、Ar、CO₂与CH₄，分析偏差AB分别为1.06 ± 0.03、1.06 ± 0.03、1.05 ± 0.03、0.86 ± 0.06与1.10 ± 0.04。 研究采用标准误差传递公式（standard error-propagation formulas）完成不确定度的传播计算，并明确考虑了因变量间的协方差。完整实验方法详见Ardoin等人（已提交至《The Cryosphere》）的研究成果。