Boundary Conditions on Quasi-Stokes Velocities in Parameterizations
Boundary Conditions on Quasi-Stokes Velocities in Parameterizations
复制标题
参数化中准斯托克斯速度的边界条件
DOI：
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发表时间：
2001
期刊：
影响因子：
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通讯作者：
P. Killworth
中科院分区：
文献类型：
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作者：
P. Killworth
摘要本文探讨了用准斯托克斯速度表示涡参数化的意义。必须使用低通时均平均密度的另一种定义（修正平均），即给定等密度线的平均深度的反演。这个定义自然地产生比欧拉平均值更轻（密度更大）的表面（地板）流体，因为具有这些密度的流体偶尔会出现在这些位置。这两种方法之间的差异在扰动幅度上是二阶的，并且在流体内部（其中存在连接两者的公式）中是如此之小。在水平边界附近，差异变为一阶，因此更加严重。现有的准斯托克斯速度和流函数的公式也在这里打破。结果表明，低通时间平均势能在一个封闭的盒子是不正确的计算从修改后的平均密度，涉及平均二次变异的误差项。最大的差异所在的那一层...
Abstract This paper examines the implications for eddy parameterizations of expressing them in terms of the quasi-Stokes velocity. Another definition of low-passed time-averaged mean density (the modified mean) must be used, which is the inversion of the mean depth of a given isopycnal. This definition naturally yields lighter (denser) fluid at the surface (floor) than the Eulerian mean since fluid with these densities occasionally occurs at these locations. The difference between the two means is second order in perturbation amplitude, and so small, in the fluid interior (where formulas to connect the two exist). Near horizontal boundaries, the differences become first order, and so more severe. Existing formulas for quasi-Stokes velocities and streamfunction also break down here. It is shown that the low-passed time-mean potential energy in a closed box is incorrectly computed from modified mean density, the error term involving averaged quadratic variability. The layer in which the largest differences ...