Annual cycle in flow of Ross Ice Shelf, Antarctica: contribution of variable basal melting
Annual cycle in flow of Ross Ice Shelf, Antarctica: contribution of variable basal melting
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DOI：
10.1017/jog.2020.61
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发表时间：
2020-08
影响因子：
3.4
通讯作者：
E. Klein;C. Mosbeux;P. Bromirski;L. Padman;Y. Bock;S. Springer;H. Fricker
中科院分区：
文献类型：
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作者：
E. Klein;C. Mosbeux;P. Bromirski;L. Padman;Y. Bock;S. Springer;H. Fricker
摘要冰架在调节南极冰盖陆地部分冰的动态损失及其对海平面上升的贡献方面起着关键作用。冰架运动的测量提供了深入了解过程修改扶壁。在这里，我们调查的季节性变化的基础上融化罗斯冰架冰流的影响。从2015年11月到2016年12月，在从冰锋到上游430公里处部署的12个GPS站测量了速度。在每个站的流动平行速度异常，相对于年平均值，是小的，在初夏（11月至1月），负2月至4月，和积极的，在南冬季（5月至9月）。大多数台站的最大速度异常达到每年数米。我们使用了一个2-D冰盖模型的RIS及其接地支流，以探索冰盖随时间变化的基础融化率的季节性响应。我们发现，融化速率的变化，夏季海洋上层加热附近的冰锋将影响未来的流量RIS及其支流冰川。然而，模拟的季节性流量变化增加的夏季基底融化附近的冰锋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。
Abstract 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.