Linear Kinematic Features (LKFs) are found everywhere in the Arctic sea-ice cover. They are strongly localized deformations often associated with the formation of leads and pressure ridges. Viscous-plastic sea-ice models start to produce LKFs at high spatial grid resolution, typically with a grid spacing below 5 km. A recent study showed that the placement of the variables on the grid plays an important role for the number of simulated LKFs. The study found that a nonconforming finite element discretization with a CD-grid placement (CD1) resolves more LKFs per degree of freedom compared to more common A,B and C-grids. A new CD-grid formulation (CD2) has just been proposed based on a conforming subgrid discretization. To analyze the resolution properties of the new CD2 approach we evaluate runs from different models (e.g FESOM, MPAS) on a benchmark problem using quadrilateral, hexagonal and triangular meshes. We found that the CD1 setup simulates more deformation structure than the CD2 approximation. This highlights the importance of the type of spatial discretization for the simulation of LKFs. Due to the higher number of degrees of freedom both CD-grids resolve more LKFs than traditional A,B and C-grids at fixed mesh level. This is an appealing feature as high spatial mesh resolution is needed in viscous-plastic sea-ice models to simulate LKFs.

翻译：线性运动特征（LKFs）普遍存在于北极海冰覆盖区域。这些高度局域化的形变通常与冰间水道和压力脊的形成相关。粘塑性海冰模型在空间网格分辨率较高时（通常网格间距小于5公里）开始产生LKFs。最新研究表明，网格变量布置方式对模拟生成的LKFs数量具有重要影响。该研究发现，与常用的A、B、C网格相比，采用CD网格布置（CD1）的非协调有限元离散格式在单位自由度下可解析更多LKFs。基于协调子网格离散格式的新型CD网格公式（CD2）刚被提出。为分析CD2方法的分辨率特性，我们利用四边形、六边形和三角形网格对基准问题开展评估，比较了不同模型（如FESOM、MPAS）的模拟结果。研究发现CD1方案模拟的形变结构多于CD2近似方案，这凸显了空间离散化类型对LKFs模拟的关键作用。在固定网格层级下，两种CD网格因具有更高自由度，均能解析比传统A、B、C网格更多的LKFs。这一特性极具吸引力，因为粘塑性海冰模型需要高空间网格分辨率才能模拟LKFs。