A permeameter for temperate ice: first results on permeability sensitivity to grain size
A permeameter for temperate ice: first results on permeability sensitivity to grain size
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DOI：
10.1017/jog.2021.136
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发表时间：
2022-02-03
影响因子：
3.4
通讯作者：
Iverson, Neal R.
中科院分区：
文献类型：
--
作者：
Fowler, Jacob R.;Iverson, Neal R.
将温带变形作为两相流动的冰流模型的结果对冰的渗透性敏感。我们已经使用定制的，掉落头的渗透器构建并开始构建，以测量温带，多晶冰的渗透性。冷水通过保持压力熔化温度的冰盘，而头部降低的速度则表明渗透率。水中的荧光素染料允许使用荧光显微镜研究水脱水的几何形状。持续时间到几个小时的水流为Darcian，对于谷物直径为1.7至8.9毫米，平均渗透率从2 x 10（-12）降低到4 x 10（-15）m（2）。在细染料（d = 2 mm）和粗（d = 7 mm）冰的测试中，平均面积加权静脉半径几乎相等，分别为41和34 mu m。这些平均半径（如果包含在Nye和Frank（1973）中稍微修改的理论中），则基于数据的回归，在最佳拟合值的2.0倍内产生了渗透率值。渗透率值取决于d（-3.4），而不是d（-2），如模型所预测的，如果静脉半径被认为与d无关。在将来的实验中，将测量渗透率对液态水含量的依赖性。
Results of ice-stream models that treat temperate ice deformation as a two-phase flow are sensitive to the ice permeability. We have constructed and begun using a custom, falling-head permeameter for measuring the permeability of temperate, polycrystalline ice. Chilled water is passed through an ice disk that is kept at the pressure-melting temperature while the rate of head decrease indicates the permeability. Fluorescein dye in the water allows water-vein geometry to be studied using fluorescence microscopy. Water flow over durations of seconds to hours is Darcian, and for grain diameter d increasing from 1.7 to 8.9 mm, average permeability decreases from 2 x 10(-12) to 4 x 10(-15) m(2). In tests with dye on fine (d = 2 mm) and coarse (d = 7 mm) ice, average area-weighted vein radii are nearly equal, 41 and 34 mu m, respectively. These average radii, if included in a theory slightly modified from Nye and Frank (1973), yield permeability values within a factor of 2.0 of best-fit values based on regression of the data. Permeability values depend on d(-3.4), rather than d(-2) as predicted by models if vein radii are considered independent of d. In future experiments, the dependence of permeability on liquid water content will be measured.