On producing sea ice deformation data sets from SAR-derived sea ice motion
On producing sea ice deformation data sets from SAR-derived sea ice motion
复制标题
从 SAR 导出的海冰运动生成海冰变形数据集
DOI：
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发表时间：
2014
期刊：
影响因子：
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通讯作者：
P. Rampal
中科院分区：
文献类型：
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作者：
S. Bouillon;P. Rampal
抽象的。提出了一种减小合成孔径雷达(SAR)海冰运动计算海冰形变场误差的方法。该方法基于两个步骤。第一步是使用从海冰轨迹获取的位置的三角测量来定义网格，在该网格上计算海冰变形的第一个估计。第二步是将特定的平滑器应用于变形场，以减少沿着海冰运动场中的不连续而产生的人工噪声。该方法被应用于RADARSAT地球物理处理器系统(RGPS)的海冰轨迹，其时间分辨率约为3天，空间分辨率约为10公里。从未滤波场和滤波场的比较中，我们估计人工噪声导致了大约60%的开场和闭场的高估。人工噪声对变形的统计分布和用多重分形分析估计的标度指数也有很大的影响。我们还表明，在广泛使用的四点形变RGPS数据集提供的变形场中也存在类似的噪声。这些发现可能会对以前的研究产生严重影响，因为对开闭度的持续高估可能会导致对铅冻结、盐排斥和海冰隆起的严重高估。
Abstract. We propose a method to reduce the error generated when computing sea ice deformation fields from synthetic aperture radar (SAR)-derived sea ice motion. The method is based on two steps. The first step consists of using a triangulation of the positions taken from the sea ice trajectories to define a mesh on which a first estimate of sea ice deformation is computed. The second step consists of applying a specific smoother to the deformation field to reduce the artificial noise that arises along discontinuities in the sea ice motion field. This method is here applied to RADARSAT Geophysical Processor System (RGPS) sea ice trajectories having a temporal and spatial resolution of about 3 days and 10 km, respectively. From the comparison between unfiltered and filtered fields, we estimate that the artificial noise causes an overestimation of about 60% of opening and closing. The artificial noise also has a strong impact on the statistical distribution of the deformation and on the scaling exponents estimated with multifractal analysis. We also show that a similar noise is present in the deformation fields provided in the widely used four-point deformation RGPS data set. These findings may have serious implications for previous studies as the constant overestimation of the opening and closing could lead to a large overestimation of freezing in leads, salt rejection and sea ice ridging.