Ice shelves regulate the ice‐ocean boundary by buttressing the flux of grounded ice into the ocean and are vulnerable to basal melt, which can lead to ice‐shelf thinning and loss of buttressing. Localized, enhanced basal melt can form basal channels, which may impact ice‐shelf stability. Here we investigate the evolution of the Getz Ice Shelf Basal Channel (GISBC) in West Antarctica using a novel suite of geophysical data, including Reference Elevation Model of Antarctica (REMA) digital elevation models, ICESat‐1 and ‐2 altimetry, Operation IceBridge altimetry and radar, and InSAR‐derived ice flow velocities. We describe basal‐channel and ice‐shelf change in both Eulerian and Lagrangian frameworks and document changes in the channel's shape and its lateral motion and estimate basal melting. We find a high degree of spatial and temporal variability in GISBC evolution, with several locations of active basal incision. Incision occurs at rates of up to 22 m a⁻¹ at the head of the channel, which is extending toward the grounding line at a rate of ~1 km a⁻¹. Freeboard heights over areas of rapid basal incision are out of hydrostatic equilibrium. The GISBC is also migrating to the northwest, perpendicular to the northeasterly ice flow direction, at an average rate of 70–80 m a⁻¹. The spatiotemporal variability of evolution of the GISBC motivates further characterization of basal channels and their impact on ice‐shelf stability, so that these effects may more readily be incorporated in ice‐ocean models predicting ice flow and sea‐level rise.

中文翻译：

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西南极洲格兹冰架上的基础河道演化

冰架通过支撑地面冰流向海洋的流动来调节冰洋边界，并且容易受到基础融化的影响，这可能导致冰架变薄和失去支撑。局部增强的基础熔体会形成基础通道，这可能会影响冰架的稳定性。在这里，我们使用一套新颖的地球物理数据，研究了南极西部盖茨冰架基础通道（GISBC）的演变，包括南极参考高程模型（REMA）数字高程模型，ICESat-1和-2高程，IceBridge高空操作雷达，InSAR产生的冰流速度。我们描述了欧拉和拉格朗日框架中的基底通道和冰架的变化，并记录了通道形状及其横向运动的变化，并估计了基底融化。我们发现GISBC演化具有高度的时空变异性，有几个活动的基底切口位置。切口的发生速度高达22 m a通道顶部的^-1处，以〜1 km a ^-1的速率朝向接地线延伸。快速基底切口区域的干舷高度超出静水平衡。GISBC还以平均70-80 m a ^-1的速率迁移到西北，垂直于东北冰的流向。GISBC演化的时空变异性进一步激发了基础河道的特征及其对冰架稳定性的影响，因此这些影响可能更容易纳入预测冰流量和海平面上升的冰洋模型中。