Comparing Glacial-Geological Evidence and Model Simulations of Ice Sheet Change since the Last Glacial Period in the Amundsen Sea Sector of Antarctica
Comparing Glacial-Geological Evidence and Model Simulations of Ice Sheet Change since the Last Glacial Period in the Amundsen Sea Sector of Antarctica
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DOI：
10.1029/2020jf005827
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发表时间：
2021-06-01
影响因子：
3.9
通讯作者：
Schaefer, Joerg M.
中科院分区：
文献类型：
--
作者：
Johnson, Joanne S.;Pollard, David;Schaefer, Joerg M.
自从类似于20000年前的最后一次冰川盛期以来，南极冰盖经历了广泛的变化，导致现在的冰盖结构要小得多。提高我们对在那次撤退中发挥重要作用的基本物理过程的了解，对于提供对未来撤退和海平面上升的更可靠的模型预测至关重要。这里，有限区域嵌套冰盖模式被应用于阿蒙森海湾(ASE)南极西部冰盖的最后一次消融，分辨率为5公里。研究了分别靠近哈德逊山脉和墨菲山的松岛冰川和教皇冰川沿线的冰盖对气候和海平面强迫的响应，并将模拟的响应与由冰川地质数据得出的冰盖减薄历史进行了比较。还评估了结果对选定的模型参数的敏感性。模型模拟预测，中部和东部海区对海洋强迫的反应大致相似，首先是变薄的快速阶段，然后是向现代形态转变的较慢阶段。尽管模拟变薄的时间与观测到的变薄时间之间存在长达5000年的不匹配，但模拟表明，冰面高度变化的上游地质记录反映了接地线附近退缩的反应。通过考虑地幔粘度、海面高度和大陆架基本滑动特性的区域差异，模型数据失配可能会得到改善。
Since the Last Glacial Maximum similar to 20,000 years ago, the Antarctic Ice Sheet has undergone extensive changes, resulting in a much smaller present-day configuration. Improving our understanding of basic physical processes that played important roles during that retreat is critical to providing more robust model projections of future retreat and sea-level rise. Here, a limited-area nested ice sheet model was applied to the last deglacial retreat of the West Antarctic Ice Sheet in the Amundsen Sea Embayment (ASE), at 5 km resolution. The ice sheet response to climate and sea-level forcing was examined at two sites along the flowlines of Pine Island Glacier and Pope Glacier, close to the Hudson Mountains and Mount Murphy respectively, and the simulated responses compared with ice sheet thinning histories derived from glacial-geological data. The sensitivity of results to selected model parameters was also assessed. The model simulations predict a broadly similar response to ocean forcing in both the central and eastern ASE, with an initial rapid phase of thinning followed by a slower phase to the modern configuration. Although there is a mismatch of up to 5,000 years between the timing of simulated and observed thinning, the modeling suggests that the upstream geological records of ice surface elevation change reflect a response to retreat near the grounding line. The model-data mismatch could potentially be improved by accounting for regional variations in mantle viscosity, sea-surface heights and basal sliding properties across the continental shelf.