A Simple Model for the Skewness of Global Sea Surface Winds
A Simple Model for the Skewness of Global Sea Surface Winds
复制标题
全球海面风偏度的简单模型
DOI：
10.1175/1520-0469(2004)061
复制
发表时间：
2004
期刊：
影响因子：
--
通讯作者：
A. Monahan
中科院分区：
文献类型：
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作者：
A. Monahan
全球海面风(纬向风和经向风)的平均值和偏斜度之间存在着很强的线性关系，即当风分量平均为正时，风分量为负偏(反之亦然)。在再分析、卫星和浮标数据中可以观察到这种关系。海面风的平均场和偏度场之间的这种关系源于Monin-Obukhov相似理论对湍流边界层预测的非线性表面阻力，因为强迫加速风的扰动比减缓风的扰动受到更大的阻力。此外，在苏拉最近的一项研究中，观测到的地面风与随机微分方程的经验拟合的结果与受脉动强迫的湍流边界层的动量方程的白噪声极限是一致的，尽管有一些不同的物理解释。
Abstract A strong linear relationship between the mean and skewness of global sea surface winds (both zonal and meridional) is shown to exist, such that where the wind component is on average positive, it is negatively skewed (and vice versa). This relationship is observed in reanalysis, satellite, and buoy data. This relationship between the mean and skewness fields of sea surface winds follows from the nonlinear surface drag predicted for a turbulent boundary layer by Monin–Obukhov similarity theory since forcing perturbations speeding the wind up are subject to a stronger drag force than perturbations slowing it down. Furthermore, it is demonstrated that the results of an empirical fit of observed surface winds to a stochastic differential equation presented in a recent study by Sura are consistent with the white-noise limit of the momentum equations for a turbulent boundary layer subject to fluctuating forcing, albeit with a somewhat different physical interpretation.