Fluctuations of a Greenlandic tidewater glacier driven by changes in atmospheric forcing: observations and modelling of Kangiata Nunaata Sermia, 1859-present
Fluctuations of a Greenlandic tidewater glacier driven by changes in atmospheric forcing: observations and modelling of Kangiata Nunaata Sermia, 1859-present
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DOI：
10.5194/tc-8-2031-2014
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发表时间：
2014-01-01
期刊：
影响因子：
5.2
通讯作者：
Weidick, A.
中科院分区：
文献类型：
--
作者：
Lea, J. M.;Mair, D. W. F.;Weidick, A.
格陵兰岛的许多冰川在经历了小冰期极大期之后，在上个世纪经历了显著的退缩。在有可能重建这一时期冰川变化的地方，它们提供了与气候记录进行比较的极好记录，以及对数值模型的校准/验证。因此，这些冰川变化记录允许测试的数值模型，试图模拟在几十年到百年的时间尺度上的冰川行为。在这里，我们提供了1859年至2012年格陵兰西南部Kangiata Nunaata Sermia（KNS）的详细行为记录，并将其与1871年至2012年之间的海洋和大气温度数据进行比较。我们还使用这些记录来评估一个完善的一维流带模型的能力，以复制行为的观察期。终端变化的记录表明，KNS推进/撤退的阶段，大气和海洋气候异常平均多年到十年的时间尺度。从合奏模型运行的结果表明，所观察到的动态可以复制。模式运行提供了一个合理的匹配观测总是需要一个显着的大气强迫分量，但不一定需要一个海洋强迫分量。虽然海洋强迫的重要性不容忽视，但这些结果表明，大气强迫的变化可能是1859年至2012年KNS终端波动的主要驱动力。我们建议，所提出的记录的细节和长度使KNS模型验证演习调查气候，产犊率和冰川动态之间的联系的理想场所。
Many tidewater glaciers in Greenland are known to have undergone significant retreat during the last century following their Little Ice Age maxima. Where it is possible to reconstruct glacier change over this period, they provide excellent records for comparison to climate records, as well as calibration/validation for numerical models. These glacier change records therefore allow for tests of numerical models that seek to simulate tidewater glacier behaviour over multi-decadal to centennial timescales. Here we present a detailed record of behaviour from Kangiata Nunaata Sermia (KNS), SW Greenland, between 1859 and 2012, and compare it against available oceanographic and atmospheric temperature data between 1871 and 2012. We also use these records to evaluate the ability of a well-established one-dimensional flow-band model to replicate behaviour for the observation period. The record of terminus change demonstrates that KNS has advanced/retreated in phase with atmosphere and ocean climate anomalies averaged over multiannual to decadal timescales. Results from an ensemble of model runs demonstrate that observed dynamics can be replicated. Model runs that provide a reasonable match to observations always require a significant atmospheric forcing component, but do not necessarily require an oceanic forcing component. Although the importance of oceanic forcing cannot be discounted, these results demonstrate that changes in atmospheric forcing are likely to be a primary driver of the terminus fluctuations of KNS from 1859 to 2012. We propose that the detail and length of the record presented makes KNS an ideal site for model validation exercises investigating links between climate, calving rates, and tidewater glacier dynamics.