Holocene accumulation and ice flow near the West Antarctic Ice Sheet Divide ice core site
Holocene accumulation and ice flow near the West Antarctic Ice Sheet Divide ice core site
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DOI：
10.1002/2015jf003668
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发表时间：
2016-05
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影响因子：
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通讯作者：
M. Koutnik;T. Fudge;H. Conway;E. Waddington;T. Neumann;K. Cuffey;C. Buizert;K. Taylor
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文献类型：
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作者：
M. Koutnik;T. Fudge;H. Conway;E. Waddington;T. Neumann;K. Cuffey;C. Buizert;K. Taylor
西南极冰盖分水岭核心（WDC）提供了一个来自南极洲中西部罗斯-阿蒙森分水岭附近的高分辨率气候记录。此外，雷达探测到的WDC站点附近的内部层已经直接从冰芯中测得，以提供该地区年龄结构的空间变化。结合使用这两个数据集，我们首先从9.2 kyr的冰芯时间尺度推断出高分辨率的全新世累积速率历史，然后确认这种气候历史与核心站点上游的内部层一致。尽管WDC距离现代冰分水岭仅24公里，但必须考虑上游冰的平流。我们评估的积累率的历史，通过使用流带模型生成内部层，我们观察到的层进行比较。结果表明，在距今9.2 kyr（B. P.）时，百年平均积累率比现代低20%以上，从9.2到2.3 kyr B. P.增加40%，在过去的2kyr B. P.，至少减少了10%;这些全新世积累率的变化在中西部南极洲大于从东南极冰芯记录推断的变化。尽管积累率发生了重大变化，但在整个全新世，区域积累模式可能与今天相似，冰分水岭的位置可能平均保持在现代位置的5公里范围内。用于重建南极西部冰量的大陆尺度冰盖模型应该包含这种积累历史。
The West Antarctic Ice Sheet Divide Core (WDC) provided a high‐resolution climate record from near the Ross‐Amundsen Divide in Central West Antarctica. In addition, radar‐detected internal layers in the vicinity of the WDC site have been dated directly from the ice core to provide spatial variations in the age structure of the region. Using these two data sets together, we first infer a high‐resolution Holocene accumulation‐rate history from 9.2 kyr of the ice‐core timescale and then confirm that this climate history is consistent with internal layers upstream of the core site. Even though the WDC was drilled only 24 km from the modern ice divide, advection of ice from upstream must be taken into account. We evaluate histories of accumulation rate by using a flowband model to generate internal layers that we compare to observed layers. Results show that the centennially averaged accumulation rate was over 20% lower than modern at 9.2 kyr before present (B.P.), increased by 40% from 9.2 to 2.3 kyr B.P., and decreased by at least 10% over the past 2 kyr B.P. to the modern values; these Holocene accumulation‐rate changes in Central West Antarctica are larger than changes inferred from East Antarctic ice‐core records. Despite significant changes in accumulation rate, throughout the Holocene the regional accumulation pattern has likely remained similar to today, and the ice‐divide position has likely remained on average within 5 km of its modern position. Continent‐scale ice‐sheet models used for reconstructions of West Antarctic ice volume should incorporate this accumulation history.