Comparative simulations of the evolution of the Greenland ice sheet under simplified Paris Agreement scenarios with the models SICOPOLIS and ISSM
Comparative simulations of the evolution of the Greenland ice sheet under simplified Paris Agreement scenarios with the models SICOPOLIS and ISSM
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DOI：
10.1016/j.polar.2018.12.003
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发表时间：
2019-09
期刊：
影响因子：
1.8
通讯作者：
M. Rückamp;R. Greve;A. Humbert
中科院分区：
文献类型：
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作者：
M. Rückamp;R. Greve;A. Humbert
格陵兰冰盖对海平面上升的贡献的预测包括气候强迫和冰流模型所使用的基本数学和数字描述所产生的不确定性。在这里，我们提供了一个比较模式的研究，与模式SICOPOLIS，使用结构网格上的浅冰近似(SIA)，和ISSM，使用高阶(HO)近似的Stokes方程在非结构网格上。从SICOPOLIS制作的古气候旋转开始，根据气候模型的RCP2.6预测，模型被强制使用两种不同的、简化的变暖情景，这与为《巴黎协定》谈判的全球变暖极限一致。与SICOPOLIS/SIA相比，ISSM/HO在冰川末端产生较低的流速，但在狭窄的出口冰川产生更大的加速。这导致ISSM/HO的海拔高度下降更大，从而对表面质量平衡产生正反馈(ISSM/HO的海拔高度下降为∼50 GT a−1更负)。在这两种模型和方案中，预计到2300年的质量损失相当于∼62-88 mm海平面。
Projections of the contribution of the Greenland ice sheet to sea level rise comprise uncertainties that arise from the imposed climate forcing and from the underlying mathematical and numerical description used by ice flow models. Here, we present a comparative modelling study with the models SICOPOLIS, using the shallow ice approximation (SIA) on a structured grid, and ISSM, using a higher-order (HO) approximation of the Stokes equation on an unstructured grid. Starting from a paleoclimatic spin-up produced by SICOPOLIS, the models are forced with two different, simplified warming scenarios based on RCP2.6 projections from climate models, which are in line with the limit of global warming negotiated for the Paris Agreement. ISSM/HO produces lower flow speeds at the glacier termini, but more acceleration in narrow outlet glaciers compared to SICOPOLIS/SIA. This leads to a larger elevation reduction for ISSM/HO, and thus a positive feedback on the surface mass balance (with that of ISSM/HO becoming ∼50 Gt a−1more negative). Across the two models and scenarios, the projected mass loss by 2300 is ∼62–88 mm sea level equivalent.