Glaciers in polar regions are sensitive to climate and ocean changes and can thin rapidly as a consequence of global warming. Digital Elevation Models (DEMs) from remote sensing observations have been widely used to detect changes in polar glaciers. DEMs from Terrestrial Radar Interferometer (TRI) have recently been used for high frequency glacier change and glacier-ocean interaction studies. However, it is unclear whether TRI DEM over a large study area can be combined directly with remote sensing observations to investigate glacier changes as well as the accuracy of TRI DEM at far range. In this study, we deployed a TRI close to Helheim Glacier, East Greenland and generated DEMs using TRI and satellite laser altimetry. We analyzed the accuracy of the TRI DEM using theoretical calculations, comparisons based on repeat observations, and comparisons with a high accurate ArcticDEM. The validation results suggest that for stable ground surfaces, the uncertainty (standard deviation) is <5 m at range < 9.8 km. Averaging across time (e.g. one hour) decreases the uncertainty almost linearly with range, over 0.5 m to 1.2 m when the range increases from 7.0 km to 10.0 km. Increasing the correlation coefficient threshold for phase unwrapping does not significantly reduce uncertainty. TRI DEMs are influenced by systematic error at far range primarily due to coarse azimuth resolution and phase unwrapping difficulties in discontinuous interferograms. As the absolute accuracy of TRI DEMs is not uniformly distributed in the range direction (farther points have worse uncertainty), our findings indicate that TRI DEMs within range of 10 km can reach <5 m uncertainty, which can be compared with DEMs obtained from remote sensing satellites to detect glacier thinning.

极地地区的冰川对气候和海洋变化很敏感，并且会因全球变暖而迅速变薄。来自遥感观测的数字高程模型 (DEM) 已被广泛用于检测极地冰川的变化。来自陆地雷达干涉仪 (TRI) 的 DEM 最近已用于高频冰川变化和冰川-海洋相互作用研究。然而，目前尚不清楚大范围研究区的 TRI DEM 是否可以直接与遥感观测相结合来研究冰川变化以及远距离 TRI DEM 的准确性。在这项研究中，我们在东格陵兰的赫尔海姆冰川附近部署了一个 TRI，并使用 TRI 和卫星激光测高仪生成了 DEM。我们使用理论计算、基于重复观察的比较分析了 TRI DEM 的准确性，并与高精度的 ArcticDEM 进行比较。验证结果表明，对于稳定的地表，不确定性（标准偏差）在 < 9.8 km 范围内小于 5 m。跨时间（例如，一小时）求平均值会随着距离几乎线性地降低不确定性，当距离从 7.0 公里增加到 10.0 公里时，不确定性会从 0.5 m 增加到 1.2 m。增加相位展开的相关系数阈值不会显着降低不确定性。TRI DEM 受到远距离系统误差的影响，主要是由于不连续干涉图中的粗方位分辨率和相位展开困难。由于 TRI DEM 的绝对精度在距离方向上不是均匀分布的（更远的点具有更严重的不确定性），我们的研究结果表明，10 km 范围内的 TRI DEM 可以达到 <5 m 的不确定性，