The majority of ice mass loss from Antarctica flows through narrow, fast sliding regions of ice. The lateral boundaries of these regions, termed shear margins, are characterized by lateral shear strains in excess of ∼10⁻³ yr⁻¹. Shear heating within these margins could warm ice significantly–even to the melting point–but other processes such as lateral advection of cold ice and fabric development compete with this effect. Radar observations can help constrain where temperate ice exists because englacial temperature increases electric conductivity which increases radar attenuation. We utilize the temperature-dependent attenuation of ice to develop a novel method for constraining englacial temperature in shear margins by combining existing thermal models with very high frequency radar depth-sounding data. We find evidence supporting temperate shear margins in 18 locations and find evidence for non-temperate margins in 37 locations, notably in the Amundsen Sea Embayment.

中文翻译：

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来自雷达深度探测数据的支持和反对南极剪切裕度的温带冰的证据

南极洲的大部分冰块损失都流经狭窄、快速滑动的冰区。这些区域的横向边界称为剪切裕度，其特征是横向剪切应变超过~10 ^-3  yr ^-1。这些边缘内的剪切加热可以使冰显着变暖，甚至达到熔点，但其他过程（例如冷冰的横向平流和织物发展）会与这种效应竞争。雷达观测有助于确定温带冰存在的位置，因为冰川温度会增加电导率，从而增加雷达衰减。我们利用冰随温度变化的衰减，通过将现有的热模型与甚高频雷达测深数据相结合，开发出一种限制剪切裕度内冰川温度的新方法。我们在 18 个地点找到了支持温带剪切边缘的证据，并在 37 个地点找到了非温带剪切边缘的证据，特别是在阿蒙森海海湾。