Ice shelves play a critical role in modulating dynamic loss of ice from the grounded portion of the Antarctic Ice Sheet and its contribution to sea-level rise. Measurements of ice-shelf motion provide insights into processes modifying buttressing. Here we investigate the effect of seasonal variability of basal melting on ice flow of Ross Ice Shelf. Velocities were measured from November 2015 to December 2016 at 12 GPS stations deployed from the ice front to 430 km upstream. The flow-parallel velocity anomaly at each station, relative to the annual mean, was small during early austral summer (November–January), negative during February–April, and positive during austral winter (May–September). The maximum velocity anomaly reached several metres per year at most stations. We used a 2-D ice-sheet model of the RIS and its grounded tributaries to explore the seasonal response of the ice sheet to time-varying basal melt rates. We find that melt-rate response to changes in summer upper-ocean heating near the ice front will affect the future flow of RIS and its tributary glaciers. However, modelled seasonal flow variations from increased summer basal melting near the ice front are much smaller than observed, suggesting that other as-yet-unidentified seasonal processes are currently dominant.

中文翻译：

---

南极洲罗斯冰架流动的年循环：可变基础融化的贡献

冰架在调节南极冰盖接地部分的冰动态损失及其对海平面上升的贡献方面发挥着关键作用。冰架运动的测量提供了对修改支撑的过程的见解。在这里，我们研究了基础融化的季节性变化对罗斯冰架冰流的影响。从 2015 年 11 月到 2016 年 12 月，在从冰锋部署到上游 430 公里的 12 个 GPS 站测量速度。与年均值相比，各站的平行流速异常在南半球初夏（11-1月）较小，在2-4月为负值，在南半球冬季（5-9月）为正值。大多数站点的最大速度异常达到每年几米。我们使用 RIS 及其接地支流的二维冰盖模型来探索冰盖对随时间变化的基础融化速率的季节性响应。我们发现融化速率对冰锋附近夏季上层海洋加热变化的响应将影响 RIS 及其支流冰川的未来流动。然而，冰锋附近夏季基础融化增加的模拟季节性流量变化比观察到的要小得多，这表明其他尚未确定的季节性过程目前占主导地位。