Decadal‐scale sensitivity of Northeast Greenland ice flow to errors in surface mass balance using ISSM
Decadal‐scale sensitivity of Northeast Greenland ice flow to errors in surface mass balance using ISSM
复制标题
使用 ISSM 计算格陵兰岛东北部冰流对表面质量平衡误差的十年尺度敏感性
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
J. Box
中科院分区：
文献类型：
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作者：
N. Schlegel;E. Larour;H. Seroussi;Mathieu Morlighem;J. Box
格陵兰冰盖的行为被认为是海平面变化的主要因素，最好在世纪和更长的时间尺度上了解。然而，在年代际时间尺度上，由于模拟地面气候的困难，以及对冰流动力过程的不完全理解，其响应不太可预测。因此，必须了解建模的进步，如提高空间分辨率或更全面的冰流方程，可能会改善冰盖对气候趋势的预测。在这里，我们研究如何精细解决气候强迫影响高分辨率冰流模型，考虑纵向应力。我们使用冰盖系统模型（ISSM）中实现的二维Shelfy-Stream近似来模拟冰流，并使用模型中嵌入的不确定性量化工具来计算东北格陵兰冰流中冰流对表面质量平衡（SMB）强迫误差的敏感性。我们的研究结果表明，该模型往往平滑的冰速度，即使在SMB的极端错误被迫。实际上，误差通过模型线性传播，导致排放不确定性为16%或1.9 Gt/yr。我们发现，质量通量是最敏感的本地错误，但也受到数百公里以外的错误，因此，准确的SMB地图的整个盆地是逼真的模拟是至关重要的。此外，敏感性分析表明，SMB强迫需要提供至少40公里的分辨率。
The behavior of the Greenland Ice Sheet, which is considered a major contributor to sea level changes, is best understood on century and longer time scales. However, on decadal time scales, its response is less predictable due to the difficulty of modeling surface climate, as well as incomplete understanding of the dynamic processes responsible for ice flow. Therefore, it is imperative to understand how modeling advancements, such as increased spatial resolution or more comprehensive ice flow equations, might improve projections of ice sheet response to climatic trends. Here we examine how a finely resolved climate forcing influences a high‐resolution ice stream model that considers longitudinal stresses. We simulate ice flow using a two‐dimensional Shelfy‐Stream Approximation implemented within the Ice Sheet System Model (ISSM) and use uncertainty quantification tools embedded within the model to calculate the sensitivity of ice flow within the Northeast Greenland Ice Stream to errors in surface mass balance (SMB) forcing. Our results suggest that the model tends to smooth ice velocities even when forced with extreme errors in SMB. Indeed, errors propagate linearly through the model, resulting in discharge uncertainty of 16% or 1.9 Gt/yr. We find that mass flux is most sensitive to local errors but is also affected by errors hundreds of kilometers away; thus, an accurate SMB map of the entire basin is critical for realistic simulation. Furthermore, sensitivity analyses indicate that SMB forcing needs to be provided at a resolution of at least 40 km.
影响因子：
18.3
作者：
Bartholomew, Ian;Nienow, Peter;Sole, Andrew
通讯作者：
Sole, Andrew