The force balance of sea ice in a numerical model of the Arctic Ocean
The force balance of sea ice in a numerical model of the Arctic Ocean
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DOI：
10.1029/97jc01454
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发表时间：
1997-09-15
影响因子：
3.6
通讯作者：
Stern, H
中科院分区：
文献类型：
--
作者：
Steele, M;Zhang, JL;Stern, H
对Hibler（1979）的海冰模型中的力平衡进行了检验。该模型预测，内部应力梯度是一个重要的力量，在北冰洋大部分地区，除了在夏季，当他们是显着的，只有离开格陵兰岛和加拿大群岛的北方海岸，内部应力梯度之间的压力梯度和粘性项的分区显示，这两个都是显着的，虽然它们在非常不同的时间尺度上运行。加速度项一般可以忽略不计，而科里奥利加海面倾斜之和很小。因此，在秋季、冬季和春季，季节平均力平衡主要是在三个大致相等大小的项之间：空气阻力、水阻力和内部应力梯度。每月平均兵力平衡情况也是如此。然而，我们发现，有一个过渡，在每周的时间尺度和每天的基础上，在一个特定的位置和时间的力平衡往往只有两个条款之间：要么空气阻力和水阻力或空气阻力和内部应力梯度之间。该模式与Thorndike和Colony [1982]的观测结果相一致，因为地转风强迫与模式的冰速度场之间有很高的相关性。这一结果进行了讨论的背景下的力平衡，我们表明，显着的内部应力梯度的存在下，并不排除高风冰相关性。分解的内部应力梯度的组成部分显示，剪切粘性力是远远不可忽略的，这对空化流体近似（其中该组件被忽略）的理论有效性提出了强烈的质疑。最后，通过改变参数P* 来检查冰压力的作用。我们发现一个很强的敏感性，在力的平衡，以及冰的厚度和速度。
The balance of forces in the sea ice model of Hibler [1979] is examined. The model predicts that internal stress gradients are an important force in much of the Arctic Ocean except in summer, when they are significant only off the northern coasts of Greenland and the Canadian Archipelago, A partition of the internal stress gradient between the pressure gradient and the viscous terms reveals that both are significant, although they operate on very different timescales. The acceleration term is generally negligible, while the sum of Coriolis plus sea surface tilt is small. Thus the seasonal average force balance in fall, winter, and spring is mostly between three terms of roughly equal magnitudes: air drag, water drag, and internal stress gradients. This is also true for the monthly average force balance. However, we find that there is a transition around the weekly timescale and that on a daily basis the force balance at a particular location and time is often between only two terms: either between air drag and water drag or between air drag and internal stress gradients. The model is in agreement with the observations of Thorndike and Colony [1982] in that the correlation between geostrophic wind forcing and the model's ice velocity field is high. This result is discussed in the context of the force balance; we show that the presence of significant internal stress gradients does not preclude high wind-ice correlation. A breakdown of the internal stress gradient into component parts reveals that the shear viscous force is far from negligible, which casts strong doubt on the theoretical validity of the cavitating fluid approximation (in which this component is neglected). Finally, the role of ice pressure is examined by varying the parameter P*. We find a strong sensitivity in terms of the force balance, as well as ice thickness and velocity.