Reactivation of Kamb Ice Stream tributaries triggers century-scale reorganization of Siple Coast ice flow in West Antarctica
Reactivation of Kamb Ice Stream tributaries triggers century-scale reorganization of Siple Coast ice flow in West Antarctica
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DOI：
10.1002/2015gl065782
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发表时间：
2015-10-28
影响因子：
5.2
通讯作者：
Carter, S. P.
中科院分区：
文献类型：
--
作者：
Bougamont, M.;Christoffersen, P.;Carter, S. P.
南极洲西部罗斯冰流内持续的百年尺度流动变化表明，该地区目前的正质量平衡可能在未来发生逆转。在这里，我们使用一个三维冰盖模式来模拟该地区的冰流超过250年。流动响应不断变化的基础属性，作为一个冰下冰碛层与水输送在一个活跃的冰下水文系统相互作用。我们发现，一个持久的弱床下的休眠卡姆冰流的支流是内部冰流的不稳定性，重组在该地区的所有冰流的来源，导致减少（正）的质量平衡在几十年内和净损失的冰在两个世纪内。这种至今未被解释的水流变化可能会在本世纪使海平面上升5毫米。为了更好地限制该地区未来海平面的变化，需要改进对地热通量和冰下水输送的估计。
Ongoing, centennial-scale flow variability within the Ross ice streams of West Antarctica suggests that the present-day positive mass balance in this region may reverse in the future. Here we use a three-dimensional ice sheet model to simulate ice flow in this region over 250years. The flow responds to changing basal properties, as a subglacial till layer interacts with water transported in an active subglacial hydrological system. We show that a persistent weak bed beneath the tributaries of the dormant Kamb Ice Stream is a source of internal ice flow instability, which reorganizes all ice streams in this region, leading to a reduced (positive) mass balance within decades and a net loss of ice within two centuries. This hitherto unaccounted for flow variability could raise sea level by 5mm this century. Better constraints on future sea level change from this region will require improved estimates of geothermal heat flux and subglacial water transport.