Variability in Basal Melting Beneath Pine Island Ice Shelf on Weekly to Monthly Timescales
Variability in Basal Melting Beneath Pine Island Ice Shelf on Weekly to Monthly Timescales
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DOI：
10.1029/2018jc014464
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发表时间：
2018-11-01
影响因子：
3.6
通讯作者：
Kim, Tae-Wan
中科院分区：
文献类型：
--
作者：
Davis, Peter E. D.;Jenkins, Adrian;Kim, Tae-Wan
海洋驱动的阿蒙森海冰架基底融化引发了许多西南极出口冰川的加速，变薄和接地线退缩。在这里，我们提出了第一个长达一年（2014年）的记录，从外部松岛冰架上的位置在次每周分辨率的基础融化率。调整的上部温跃层，当地风强迫垂直埃克曼速度的变化是主要控制在每周到每月的时间尺度上的基底融化。在这些时间尺度上，大气-冰-海洋表面热通量或修改后的绕极深水平流的变化没有发挥明显的作用。我们建议，在其他年份，加深的温跃层在松岛湾驱动的较长的时间尺度过程可能抑制了当地风强迫高频上部温跃层高度变异和基底融化的影响。这突出了不同的过程之间的复杂的相互作用和他们的时间尺度，设置松岛冰架下面的基础融化率。简明的语言摘要冰架南极冰盖的浮动延伸是从下面融化时，与温暖的海洋沃茨接触。它们融化的速度对于控制南极洲对未来海平面上升的贡献尤为重要，极端的基底融化甚至可能导致南极西部冰盖迅速崩溃。在这里，我们使用的第一个高分辨率的时间序列的基础上观察到的融化松岛冰架下的阿蒙森海部门西南极洲，探讨是什么设置的融化率在短时间尺度上。我们发现，在2014年，当地的风模式是特别重要的，因为它们能够改变松岛冰架下的海洋温度。然而，在其他年份，当地的风模式似乎不那么重要，突出了冰架和它漂浮的海洋之间存在的复杂相互作用。
Ocean-driven basal melting of Amundsen Sea ice shelves has triggered acceleration, thinning, and grounding line retreat on many West Antarctic outlet glaciers. Here we present the first year-long (2014) record of basal melt rate at sub-weekly resolution from a location on the outer Pine Island Ice Shelf. Adjustment of the upper thermocline to local wind forced variability in the vertical Ekman velocity is the dominant control on basal melting at weekly to monthly timescales. Atmosphere-ice-ocean surface heat fluxes or changes in advection of modified Circumpolar Deep Water play no discernible role at these timescales. We propose that during other years, a deepening of the thermocline in Pine Island Bay driven by longer timescale processes may have suppressed the impact of local wind forcing on high-frequency upper thermocline height variability and basal melting. This highlights the complex interplay between the different processes and their timescales that set the basal melt rate beneath Pine Island Ice Shelf.Plain Language Summary Ice shelvesthe floating extensions of the Antarctic ice sheetare melted from beneath when in contact with warm ocean waters. The rate at which they melt is especially important for controlling Antarctica's contribution to future sea level rise, and extreme basal melting may even be capable of causing the West Antarctic Ice Sheet to rapidly collapse. Here we use the first high resolution time series of basal melting observed beneath Pine Island Ice Shelf in the Amundsen Sea sector of West Antarctica to explore what sets the melt rate on short timescales. We find that during 2014, the local wind patterns are particularly important, as they are capable of changing the ocean temperature beneath Pine Island Ice Shelf. In other years, however, local wind patterns seem less important, highlighting the complex interactions that exist between the ice shelf and the ocean upon which it floats.