Simulating the ice-thickness distribution in a coupled climate model
Simulating the ice-thickness distribution in a coupled climate model
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DOI：
10.1029/1999jc000113
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发表时间：
2001-02-15
影响因子：
3.6
通讯作者：
Eby, M
中科院分区：
文献类型：
--
作者：
Bitz, CM;Holland, MM;Eby, M
研究了全球耦合模式中的气候模拟，使用了一个具有复杂热力学的动力-热力学海冰和雪模式，并对多个冰层厚度进行了次网格尺度参数化。除了海冰部分，该模式还包括一个完整的原始方程海洋和一个简单的能量-水分平衡大气。介绍了一种厚度空间拉格朗日冰厚分布公式。该方法设计为使用更少的厚度类别，因为它可以调整到最需要的地方放置分辨率，并且它没有倾向于平滑欧拉分布的扩散效应。实验表明，该模式能较好地模拟北极平均气候。将模式结果与两层海冰模式的模拟结果进行比较，发现北极和北大西洋北部的气候对冰厚度分布的解析比较敏感。冰层厚度的分布使得通过弗拉姆海峡的冰出口更加多变，与北大西洋的经向翻转有更强的联系。与欧拉方法相比，冰层厚度分布的拉格朗日公式允许包含垂直温度分布。我们发现，与Semtner零层热力学模拟相比，我们的模型中冰的增长速度和海洋表面的盐度不同，冰和雪中的垂直温度分布得到了很好的分辨，并采用了显式的盐袋参数化。尽管这些差异对北极的气候很重要，但冰层厚度分布的影响更为显著，并延伸到北大西洋北部。敏感性实验表明，在这些模拟中，具有类似于50厘米垂直温度分辨率的五种冰厚度类别捕捉到了冰厚度分布对海冰存在时跨表面的热量和淡水交换的影响。
Climate simulations in a global coupled model are investigated using a dynamic-thermodynamic sea ice and snow model with sophisticated thermodynamics and a subgrid scale parameterization for multiple ice thicknesses. In addition to the sea ice component, the model includes a full primitive-equation ocean and a simple energy-moisture balance atmosphere. We introduce a formulation of the ice thickness distribution that is Lagrangian in thickness-space. The method is designed to use fewer thickness categories because it adjusts to place resolution where it is needed most and it is free of diffusive effects that tend to smooth Eulerian distributions. Experiments demonstrate that the model does reasonably well in simulating the mean Arctic climate. We find the climate of the Arctic and northern North Atlantic is sensitive to resolving the ice-thickness distribution when comparing the model results to a simulation with a two-level sea ice model. The ice-thickness distribution causes ice export through Fram Strait to be more variable and more strongly linked to meridional overturning in the North Atlantic Ocean.The Lagrangian formulation of the ice-thickness distribution allows for the inclusion of a vertical temperature profile with relative ease compared to an Eulerian method. We find ice growth rates and ocean surface salinity differ in our model with a well-resolved vertical temperature profile in the ice and snow and an explicit brine-pocket parameterization compared to a simulation with Semtner zero-layer thermodynamics. Although these differences are important for the climate of the Arctic, the effects of an ice thickness distribution are more dramatic and extend into the northern North Atlantic. Sensitivity experiments indicate that five ice-thickness categories with similar to 50-cm vertical temperature resolution capture the effects of the ice-thickness distribution on the heat and freshwater exchange-across the surface in the presence of sea ice in these simulations.