Basal motion of ice sheets depends in part on the roughness and material properties of the subglacial bed and the occurrence of water. To date, basal motion represents one of the largest uncertainties in ice-flow models. It is that component of the total flow velocity that can change most rapidly and can, therefore, facilitate rapid variations in dynamic behaviour. In this study, we investigate the subglacial properties of the East Antarctic Ice Sheet by statistically analysing the roughness of the bed topography, inferred from radio-echo sounding measurements. We analyse two sets of roughness parameters, one derived in the spatial and the other in the spectral domain, with two roughness parameters each. This enables us to compare the suitability of the four roughness parameters to classify the subglacial landscapes below the ice sheet. We further investigate the relationship of the roughness parameters with observed surface flow velocity and modelled basal temperatures of the ice sheet. We find that one of the roughness parameters, the Hurst exponent derived in the spatial domain, coincides with the thermal condition at the base of the ice sheet for slow flow velocities and varies with flow velocity.

中文翻译：

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东南极冰盖的基础粗糙度与流速和基础热状态的关系

冰盖的基础运动部分取决于冰下床的粗糙度和材料特性以及水的存在。迄今为止，基础运动是冰流模型中最大的不确定性之一。它是总流速中变化最快的部分，因此可以促进动态行为的快速变化。在这项研究中，我们通过统计分析从无线电回波探测测量推断的床地形的粗糙度来研究东南极冰盖的冰下特性。我们分析了两组粗糙度参数，一组在空间中导出，另一组在光谱域中导出，每组有两个粗糙度参数。这使我们能够比较四个粗糙度参数对冰盖下方冰下景观进行分类的适用性。我们进一步研究了粗糙度参数与观测到的表面流速和冰盖模拟基础温度的关系。我们发现其中一个粗糙度参数，即在空间域中导出的赫斯特指数，与冰盖底部的热条件一致，用于慢流速并随流速而变化。