Diffusivity and Solubility of H 2 in Ice Ih: Implications for the Behavior of H 2 in Polar Ice
Diffusivity and Solubility of H 2 in Ice Ih: Implications for the Behavior of H 2 in Polar Ice
复制标题
H 2 在冰中的扩散率和溶解度 Ih：对极地冰中 H 2 行为的影响
DOI：
10.1029/2020jd033840
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Saltzman, Eric S.
中科院分区：
文献类型：
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作者：
Patterson, John D.;Saltzman, Eric S.
利用极地积雪空气和冰芯重建古大气H2将有助于更好地了解H2的地球化学循环以及它如何受到气候变化和人类活动的影响。在这项研究中，渗透率，扩散率和溶解度的H2实验确定在冰Ih在相关的极地冰盖（199-253 K）的温度。实验数据与简化的扩散模型结合使用，以评估以下方面的影响：（a）H2从加压封闭气泡扩散到极地积雪中的开放孔隙，（B）冰盖中H2梯度的扩散平滑，以及（c）冰芯样品中H2的取芯后扩散损失。结果表明，开放和封闭的孔隙之间的扩散平衡很可能是在雪锁定区实现。大气变化的扩散平滑是重要的，应该在千年时间尺度的大气重建中加以考虑。气泡冰样品的扩散损失是足够慢的，样品可以有意义的分析后，存储在一年左右的H2。这些结果表明，冰中H2的流动性不应排除从积雪空气和冰芯重建古大气H2。
Reconstructions of paleoatmospheric H2using polar firn air and ice cores would lead to a better understanding of the H2biogeochemical cycle and how it is influenced by climate change and human activity. In this study, the permeability, diffusivity, and solubility of H2are determined experimentally in ice Ih at temperatures relevant to polar ice sheets (199–253 K). The experimental data are used in conjunction with simplified diffusion models to assess the implications for: (a) Diffusion of H2from pressurized closed bubbles to open pores in polar firn, (b) diffusive smoothing of H2gradients in the ice sheet, and (c) post‐coring diffusive losses of H2from ice core samples. The results indicate that diffusive equilibrium between open and closed pores is likely achieved in the firn lock‐in zone. Diffusive smoothing of atmospheric variations is significant and should be accounted for in atmospheric reconstructions on millennial time scales. Diffusive losses from a bubbly ice sample are sufficiently slow that samples may be meaningfully analyzed for H2after storage on the order of a year. These results suggest that the mobility of H2in ice should not preclude the reconstruction of paleoatmospheric H2from firn air and ice cores.