A 2700-year annual timescale and accumulation history for an ice core from Roosevelt Island, West Antarctica
A 2700-year annual timescale and accumulation history for an ice core from Roosevelt Island, West Antarctica
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DOI：
10.5194/cp-15-751-2019
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发表时间：
2017-08
影响因子：
4.3
通讯作者：
Paul Kjaer;Helle A. Fudge;Tyler J. Lee;James E. Riis;M. Winstrup;P. Vallelonga;H. Kjær;T. Fudge;James E. Lee;Marie H. Riis;R. Edwards;N. Bertler;T. Blunier;E. Brook;C. Buizert;G. Ciobanu;H. Conway;D. Dahl-Jensen;Aja Ellis;B. D. Emanuelsson;R. Hindmarsh;E. Keller;A. Kurbatov;P. Mayewski;P. Neff;Rebecca L. Pyne;M. Simonsen;A. Svensson;Andrea Tuohy;E. Waddington;Sarah D. Wheatley
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文献类型：
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作者：
Paul Kjaer;Helle A. Fudge;Tyler J. Lee;James E. Riis;M. Winstrup;P. Vallelonga;H. Kjær;T. Fudge;James E. Lee;Marie H. Riis;R. Edwards;N. Bertler;T. Blunier;E. Brook;C. Buizert;G. Ciobanu;H. Conway;D. Dahl-Jensen;Aja Ellis;B. D. Emanuelsson;R. Hindmarsh;E. Keller;A. Kurbatov;P. Mayewski;P. Neff;Rebecca L. Pyne;M. Simonsen;A. Svensson;Andrea Tuohy;E. Waddington;Sarah D. Wheatley
抽象的。我们给出了西南极罗斯冰架罗斯福岛气候演变(赖斯)冰芯2700年的年代学和积雪历史。核心添加了关于南极洲一个原本限制较少的部分过去积累变化的信息。时间刻度是通过识别高分辨率杂质记录中的年度周期来构建的，它构成了2017年罗斯福岛冰芯年代学(RICE17)的最高部分。火山和甲烷与WAIS Divide冰芯的WD2014年表相匹配的验证表明，这两个时间尺度非常一致。在另一篇论文中，与WAIS分水岭相匹配的气体被用来延长无法识别年层的核心更深部分的时间尺度。根据每年确定的时间尺度，我们制作了罗斯福岛过去积雪的记录。堆积历史表明，罗斯福岛在公元前700年至1300年之间经历了轻微的堆积速率增加，平均堆积0.25±0.02m水当量(W.E.)每年。自公元1300年以来，积累率的趋势一直是负的，17世纪中叶以后下降速度加快。罗斯福岛的海流积累率为0.210±0.002米西经。Yr−1(1965年以来的平均值，±2σ)，并且正在迅速下降，趋势相当于0.8 mm yr−2。自1960年代中期以来观察到的下降速度是前几个世纪长期下降趋势的8倍，十年平均累积速率始终低于平均水平。先前的研究表明，罗斯福岛的积累率与阿蒙森海平面低的位置和强度有很强的联系，而阿蒙森海平面的位置和强度对区域海冰范围有重大影响。因此，罗斯福岛积累率的下降可以用最近加强的海平面和罗斯海东部的海冰扩大来解释。因此，1965年CE观察到的水稻积累率开始迅速下降，可能标志着区域海冰面积开始显着增加。
Abstract. We present a 2700-year annually resolved chronology and snow accumulation history for the Roosevelt Island Climate Evolution (RICE) ice core, Ross Ice Shelf, West Antarctica. The core adds information on past accumulation changes in an otherwise poorly constrained sector of Antarctica. The timescale was constructed by identifying annual cycles in high-resolution impurity records, and it constitutes the top part of the Roosevelt Island Ice Core Chronology 2017 (RICE17). Validation by volcanic and methane matching to the WD2014 chronology from the WAIS Divide ice core shows that the two timescales are in excellent agreement. In a companion paper, gas matching to WAIS Divide is used to extend the timescale for the deeper part of the core in which annual layers cannot be identified. Based on the annually resolved timescale, we produced a record of past snow accumulation at Roosevelt Island. The accumulation history shows that Roosevelt Island experienced slightly increasing accumulation rates between 700 BCE and 1300 CE, with an average accumulation of 0.25±0.02 m water equivalent (w.e.) per year. Since 1300 CE, trends in the accumulation rate have been consistently negative, with an acceleration in the rate of decline after the mid-17th century. The current accumulation rate at Roosevelt Island is 0.210±0.002 m w.e. yr−1 (average since 1965 CE, ±2σ), and it is rapidly declining with a trend corresponding to 0.8 mm yr−2. The decline observed since the mid-1960s is 8 times faster than the long-term decreasing trend taking place over the previous centuries, with decadal mean accumulation rates consistently being below average. Previous research has shown a strong link between Roosevelt Island accumulation rates and the location and intensity of the Amundsen Sea Low, which has a significant impact on regional sea-ice extent. The decrease in accumulation rates at Roosevelt Island may therefore be explained in terms of a recent strengthening of the ASL and the expansion of sea ice in the eastern Ross Sea. The start of the rapid decrease in RICE accumulation rates observed in 1965 CE may thus mark the onset of significant increases in regional sea-ice extent.