Pore space percolation in sea ice single crystals
Pore space percolation in sea ice single crystals
复制标题
海冰单晶中的孔隙空间渗透
DOI：
10.1029/2008jc005145
复制
发表时间：
2009
影响因子：
--
通讯作者：
K. Golden
中科院分区：
文献类型：
--
作者：
D. Pringle;J. Miner;H. Eicken;K. Golden
[1]我们用X射线层析成像技术对海冰单晶体进行了成像，并用逾渗理论描述了孔隙空间的热演化过程。在-18 °C和-3 °C之间，孔隙率从2%到12%不等，我们发现了近乎平行的晶内盐水层阵列，其连通性和复杂的形态随温度而变化。我们已经计算出关键的孔隙度依赖函数的经典渗流理论直接从热驱动的孔隙空间演化的单个样品。这种分析是新颖的天然材料，并提供了第一个直接证明的连接阈值在海冰的盐水微观结构。在以前的工作中，这一关键行为已间接推断从多晶样品中的体积性质测量。从有限尺度分析中，我们发现垂直临界孔隙度pc，v = 4.6 ± 0.7%。我们发现横向各向异性与pc，ε = 9 ± 2%平行的层和pc，perp = 14 ± 4%垂直于他们。通过在盐水层之间形成细颈，在较高的盐水体积下建立横向连通性。我们将这些结果与使用双孔隙度概念模型测得的体积直流电导率和流体渗透率的各向异性。我们的研究结果揭示了海冰复杂的微观结构，突出了单晶各向异性和一个现实的传输性能模型的基础上渗透理论的海冰的一步。我们提出了完整的实验细节，我们的成像和分割方法的基础上的相位关系制定更广泛地适用于冰溶质系统。
[1] We have imaged sea ice single crystals with X-ray computed tomography, and characterized the thermal evolution of the pore space with percolation theory. Between −18°C and −3°C the porosity ranged from 2 to 12% and we found arrays of near-parallel intracrystalline brine layers whose connectivity and complex morphology varied with temperature. We have computed key porosity-dependent functions of classical percolation theory directly from the thermally driven pore space evolution of an individual sample. This analysis is novel for a natural material and provides the first direct demonstration of a connectivity threshold in the brine microstructure of sea ice. In previous works this critical behavior has been inferred indirectly from bulk property measurements in polycrystalline samples. From a finite-size scaling analysis we find a vertical critical porosity pc,v = 4.6 ± 0.7%. We find lateral anisotropy with pc,pll = 9 ± 2% parallel to the layers and pc,perp = 14 ± 4% perpendicular to them. Lateral connectivity is established at higher brine volumes by the formation of thin necks between the brine layers. We relate these results to measured anisotropy in the bulk dc conductivity and fluid permeability using a dual porosity conceptual model. Our results shed new light on the complex microstructure of sea ice, highlighting single crystal anisotropy and a step toward a realistic transport property model for sea ice based on percolation theory. We present full experimental details of our imaging and segmentation methodology based on a phase relation formulation more widely applicable to ice-solute systems.