Modifications to Internal Tide Conversion Parameterizations and Implementation into Barotropic Ocean Models

Parameterization of the tidal energy conversion from barotropic to baroclinic modes through internal tide generation over rough and steep submarine topography is a necessary dissipative force for barotropic ocean models. We present and unify two forms of parameterizations that differ by assuming that wave generation is either only due to the local topographic features, or that it includes the effects of nonlocal topographic features. Previously reported implementation schemes on structured grids are extended to unstructured grids. A positive definite modification to the nonlocal generation formulation is recommended to ensure dissipation everywhere. Modifying the buoyancy frequency variable used in the formulations, in order to redistribute some of the dissipation from shallow water into deeper waters, is also proposed. MATLAB functions to compute the necessary parameters on both structured and unstructured grids are highlighted and made available.

对通过粗糙且陡峭的海底地形产生内部潮汐，从而将潮能从斜压波模式转换为正压波模式的参数化研究，是斜压海洋模型中不可或缺的耗散力。本文提出并统一了两种参数化形式，这两种形式分别基于波的产生仅由局部地形特征引起，或包括非局部地形特征影响的假设。先前在规则网格上的实施方案被扩展至非规则网格。为了确保各处均存在耗散，建议对非局部产生公式进行正定修正。此外，还提出修改用于公式的浮力频率变量，以将部分耗散从浅水区域重新分配至更深的水层。特别强调并提供了在规则网格和非规则网格上计算必要参数的 MATLAB 函数，并使其可供使用。