Aufeis are sheets of ice unique to cold regions that originate from repeated flooding and freezing events during the winter. They have hydrological importance associated with summer flows and winter insulation, but little is known about the seasonal dynamics of the unfrozen sediment layer beneath them. This layer may support perennial groundwater flow in regions with otherwise continuous permafrost. For this study, ground penetrating radar (GPR) were collected in September 2016 (maximum thaw) and April 2017 (maximum frozen) at the Kuparuk aufeis field on the North Slope of Alaska. Supporting surface nuclear magnetic resonance data were collected during the maximum frozen campaign. These point‐in‐time geophysical data sets were augmented by continuous subsurface temperature data and periodic Structure‐from‐Motion digital elevation models collected seasonally. GPR and difference digital elevation model data showed up to 6 m of ice over the sediment surface. Below the ice, GPR and nuclear magnetic resonance identified regions of permafrost and regions of seasonally frozen sediment (i.e., the active layer) underlain by a substantial lateral talik that reached >13‐m thickness. The seasonally frozen cobble layer above the talik was typically 3‐ to 5‐m thick, with freezing apparently enabled by relatively high thermal diffusivity of the overlying ice and rock cobbles. The large talik suggests that year‐round groundwater flow and coupled heat transport occurs beneath much of the feature. Highly permeable alluvial material and discrete zones of apparent groundwater upwelling indicated by geophysical and ground temperature data allows direct connection between the aufeis and the talik below.

中文翻译：

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从地球物理方法推断出的奥菲斯特征的季节性地下解冻动力学

Aufeis是寒冷地区特有的冰块，其起源于冬季反复发生的洪水和冰冻事件。它们具有与夏季水流和冬季隔热相关的水文重要性，但对其下方未冻结的沉积物层的季节动态知之甚少。该层可以支持永久性多年冻土地区的常年地下水流。对于这项研究，2016年9月（最大解冻）和2017年4月（最大冻结）在阿拉斯加北坡的Kuparuk aufeis油田收集了探地雷达（GPR）。在最大的冻结活动期间收集了支持表面的核磁共振数据。这些时间点地球物理数据集得到了连续地下温度数据和季节性收集的周期性“动动”数字高程模型的补充。GPR和差分数字高程模型数据显示，沉积物表面上的冰层长达6 m。在冰之下，GPR和核磁共振确定了多年冻土区域和季节性冻结的沉积物（即活性层）区域，该区域下方有一个厚度大于13-m的大量侧石。滑石粉上方季节性冻结的鹅卵石层通常为3至5 m厚，上面的冰和岩石卵石的相对较高的热扩散率显然使冻结得以实现。较大的标签表明，全年的地下水流量和热传递耦合发生在大部分特征之下。