Evaluation of a numerical model of the British–Irish ice sheet using relative sea‐level data: implications for the interpretation of trimline observations
Evaluation of a numerical model of the British–Irish ice sheet using relative sea‐level data: implications for the interpretation of trimline observations
复制标题
使用相对海平面数据评估英国-爱尔兰冰盖数值模型：对修剪线观测结果解释的影响
DOI：
10.1002/jqs.2552
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发表时间：
2012
影响因子：
2.3
通讯作者：
R. Edwards
中科院分区：
文献类型：
--
作者：
J. Kuchar;G. Milne;A. Hubbard;H. Patton;S. Bradley;I. Shennan;R. Edwards
由于本地和非本地信号之间的相互作用，不列颠群岛的冰川均衡调整（GIA）非常复杂。最近的一些研究使用相对海平面数据模拟了不列颠群岛的 GIA 响应。本研究通过使用数值冰川模型的输出作为 GIA 模型的输入来扩展之前的分析。这是迈向更真实的 GIA 模型的必要一步，尽管对更新世晚期的主要冰盖也进行过类似的研究，但这是首次针对不列颠群岛进行此类研究。我们测试了三种重建，根据其最大程度的体积分为“最小”、“中值”和“最大”，并发现可以获得良好的数据模型拟合。海平面数据显然更倾向于最小重建。测试的冰重建不受过去冰范围（横向和垂直）的地貌信息的限制。因此，重建的范围超出了许多信息所暗示的范围，特别是在冰厚度方面。然而，值得注意的是，重建结果与来自中部山区（例如苏格兰高地）的许多海平面数据产生了良好的拟合，这支持了这样的观点：通常用作古冰面位置约束的修剪线实际上是在从暖基冰向冷基冰过渡时形成的特征，因此标志着对冰面高度的最小约束。根据数据与模型的不匹配，提出了改进冰模型重建的建议。然而，在许多地方，不适应的原因可能是由于非本地的、主要是芬诺斯坎迪亚的冰，因此解释并不简单。因此，我们建议未来此类分析考虑芬诺斯坎迪亚和不列颠群岛的模型和观测结果。版权所有 © 2012 约翰·威利父子有限公司
The glacial isostatic adjustment (GIA) of the British Isles is complex due to the interplay between local and non‐local signals. A number of recent studies have modelled the GIA response of the British Isles using relative sea‐level data. This study extends these previous analyses by using output from a numerical glaciological model as input to a GIA model. This is a necessary step towards more realistic GIA models, and although there have been similar studies for the major late Pleistocene ice sheets, this is the first study to do so for the British Isles. We test three reconstructions, classed as ‘minimal’, ‘median’ and ‘maximal’ in terms of their volume at maximum extent, and find it is possible to obtain good data–model fits. The minimal reconstruction is clearly preferred by the sea‐level data. The ice reconstructions tested were not constrained by geomorphological information of past ice extent (lateral and vertical). As a consequence, the reconstructions extend further than much of this information suggests, particularly in terms of ice thickness. It is notable, however, that the reconstructions produce good fits to many sea‐level data from central, mountainous regions (e.g. Scottish highlands), which lends support to the suggestion that trimlines, often used as an constraint on the palaeo ice surface location, are in fact features formed at the transition from warm‐ to cold‐based ice and so mark a minimum constraint on the ice surface altitude. Based on data–model misfits, suggestions are made for improving the ice model reconstructions. However, in many locations, the cause of the misfit could be due to non‐local, predominantly Fennoscandian ice and so interpretation is not straightforward. As a result, we suggest that future analyses of this type consider models and observations for both Fennoscandia and the British Isles. Copyright © 2012 John Wiley & Sons, Ltd.