Open water production in Arctic sea ice: Satellite measurements and model parameterizations
Open water production in Arctic sea ice: Satellite measurements and model parameterizations
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北极海冰的开放水域生产：卫星测量和模型参数化
DOI：
10.1029/95jc02306
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发表时间：
1995
影响因子：
--
通讯作者：
R. Kwok
中科院分区：
文献类型：
--
作者：
H. Stern;D. Rothrock;R. Kwok
从1992年至1994年，来自ERS 1号航天器的连续合成孔径雷达图像被例行用作阿拉斯加合成孔径雷达设施地球物理处理器系统的输入，以产生5公里网格上的海冰位移矢量。我们已经将这些产品中的大约5000个（由近70万个位移矢量组成）组合成一组914个冰运动条带或马赛克，这些条带或马赛克（大部分）跨越3天的间隔。对于每个条带，我们根据5公里网格单元面积的变化计算引线的打开和关闭。我们还计算运动的面积平均变形或应变不变量。小规模（几公里）的铅活动可以参数化相当好的大规模（几百公里）的应变不变量。海冰模型通过其本构方程隐含地包含这样的参数化。Hibler（1979）的著名模型采用了粘塑性流变学和椭圆屈服曲线，与我们的数据吻合得很好。关于这种理论关系的数据的方差小于海冰运动的随机模型所建议的方差。数据还表明，剪切变形有助于打开和关闭的铅。具有两类或两级冰厚的模型一般不考虑冰密集度演变过程中的剪切变形，也不考虑冰因脊化而重新分布。我们将展示如何将这些功能添加到两级模型。然而，我们认为，开放水域，薄冰，厚冰组成的三级模型更适合于适当的治疗开放水域生产，我们提出了这样一个模型。
Sequential synthetic aperture radar (SAR) images from the ERS 1 spacecraft were routinely used as input to the Geophysical Processor System at the Alaska SAR Facility from 1992 through 1994 to produce sea ice displacement vectors on a 5-km grid. We have combined some 5000 of these products, consisting of nearly 700,000 displacement vectors, into a set of 914 strips or mosaics of ice motion that span (mostly) 3-day intervals. For each strip we compute the opening and closing of leads based on the change in area of the 5-km grid cells. We also compute the area-averaged deformation or strain invariants of the motion. The small-scale (several kilometer) lead activity can be parameterized fairly well in terms of the large-scale (several hundred kilometer) strain invariants. Sea ice models implicitly contain such a parameterization through their constitutive equations. The well-known model of Hibler (1979) that uses a viscous-plastic rheology and an elliptical yield curve is in good agreement with our data. The variance in the data about this theoretical relationship is less than that suggested by a random model of sea ice motion. The data also indicate that shearing deformation contributes to the opening and closing of leads. Models with two categories or levels of ice thickness generally do not take shearing deformation into account in the evolution of the ice concentration, nor do they redistribute ice as a result of ridging. We show how to add these features to two-level models. However, we argue that three-level models consisting of open water, thin ice, and thick ice are much better suited to the proper treatment of open water production, and we present such a model.