Chu Winnie, Hilger Andrew M, Culberg Riley, Schroeder Dustin M, Jordan Thomas M, Seroussi Helene, Young Duncan A, Blankenship Donald D, Vaughan David G
School of Earth and Atmospheric Science Georgia Institute of Technology Atlanta GA USA.
Department of Electrical Engineering Stanford University Stanford CA USA.
J Geophys Res Earth Surf. 2021 Oct;126(10):e2021JF006296. doi: 10.1029/2021JF006296. Epub 2021 Oct 22.
The Amundsen Sea Embayment of the West Antarctic Ice Sheet contains Thwaites and Pine Island Glaciers, two of the most rapidly changing glaciers in Antarctica. To date, Pine Island and Thwaites Glaciers have only been observed by independent airborne radar sounding surveys, but a combined cross-basin analysis that investigates the basal conditions across the Pine Island-Thwaites Glaciers boundary has not been performed. Here, we combine two radar surveys and correct for their differences in system parameters to produce unified englacial attenuation and basal relative reflectivity maps spanning both Pine Island and Thwaites Glaciers. Relative reflectivities range from -24.8 to +37.4 dB with the highest values beneath fast-flowing ice at the ice sheet margin. By comparing our reflectivity results with previously derived radar specularity and trailing bed echoes at Thwaites Glacier, we find a highly diverse subglacial landscape and hydrologic conditions that evolve along-flow. Together, these findings highlight the potential for joint airborne radar analysis with ground-based seismic and geomorphological observations to understand variations in the bed properties and cross-catchment interactions of ice streams and outlet glaciers.
西南极冰盖的阿蒙森海湾区包含了思韦茨冰川和松岛冰川，这是南极洲变化最迅速的两条冰川。迄今为止，松岛冰川和思韦茨冰川仅通过独立的机载雷达测深调查进行过观测，但尚未开展一项综合跨流域分析来研究松岛冰川与思韦茨冰川边界处的基底状况。在此，我们将两次雷达调查结合起来，并对其系统参数差异进行校正，以生成涵盖松岛冰川和思韦茨冰川的统一冰内衰减和基底相对反射率图。相对反射率范围为-24.8至+37.4分贝，最高值出现在冰盖边缘快速流动的冰体下方。通过将我们的反射率结果与之前在思韦茨冰川得出的雷达镜面反射和尾随床面回波进行比较，我们发现了一个高度多样的冰下地貌和随流变化的水文条件。这些发现共同凸显了联合机载雷达分析与地面地震和地貌观测，以了解冰流和出口冰川的床面特性变化及跨集水区相互作用的潜力。
