Global calculation of the internal M2-tide generation with a horizontal direction (mode 1)

this dataset represents the barotropic-to-baroclinic energy transfer of the m2-tide’s first mode in the global ocean. the method is based on linear theory and, for the first time, resolves the horizontal direction of the modal internal tide generation without resorting to wkbj-scaling (see pollmann et al., 2019: resolving the horizontal direction of internal tide generation, journal of fluid dynamics). by construction, the conversion field is positive definite and hence ready to use in tidal mixing parameterizations.supercritical slopes, where linear theory breaks down, are masked in the calculations. the details of the calculations and the analysis of the results is described in the manuscript „resolving the horizontal direction of internal tide generation: global application for the m2-tide’s first mode“, pollmann and nycander, under revision at journal of physical oceanography. please refer to this publication when using this data set. the data set includes:a) the anisotropic barotropic-to-baroclinic energy flux fphi (w/rad) at a horizontal resolution of 0.5°x0.5° and with 1000 directions in wavenumber angle space. the angle phi is zero in eastward direction, 90° in northward direction etc.b) the total conversion conv (w/m^2), obtained by scaling the energy flux fphi by the effective patch area pi*rg^2 and integrating over all angular points. each value of conv and fphi is representative of a circular patch with a radius of 2.5*rg, whose center is located on the 0.5°x0.5° horizontal grid. the tidal currents (from tpxo9.1; egbert and erofeeva, 2002), the stratification (from gouretski and koltermann, 2004) and hence wavenumbers and phase velocities, and the topography (srtm30+; becker et al., 2009) from the entire patch contribute to the estimates of fphi and conv given at the respective patch center.c) the standard deviation of the two-dimensional gaussian taper, rg, which is applied to the high-resolution topography (srtm30+) in each patch to ensure a smooth decrease toward the patch average at the patch boundary.d) the bottom depth based on srtm30+.e) the mask that excludes steep continental slopes and shelves, deep ocean trenches and shallow seas from the calculations, based on the geomorphology data of harris et al., 2014, at 0.5° and 1/120° resolution.

本数据集展现了全球海洋中m2潮汐第一模态的斜压-纬向能传递过程。研究方法基于线性理论，并首次通过无需采用WKB缩放（参见Pollmann等，2019年：《解决内部潮汐生成的水平方向》，流体动力学杂志）的方式，解析了模式内部潮汐生成的水平方向。构造上，转换场为正定，因此可直接用于潮汐混合参数化。在计算中，线性理论失效的超临界斜率被屏蔽。计算细节及结果分析详述于稿件《解决内部潮汐生成的水平方向：m2潮汐第一模态的全球应用》，Pollmann和Nycander著，正在《物理海洋学杂志》修订中。使用本数据集时，请参阅该出版物。数据集包括：a）在水平分辨率为0.5°x0.5°，波数角空间方向数为1000的情况下，各向异性的斜压-纬向能通量fphi（w/rad）。角度φ在向东方向为零，向北方向为90°等。b）通过缩放能量通量fphi以有效区块面积π*rg^2，并整合所有角度点而得到的总转换量conv（w/m^2）。conv和fphi的每个值均代表一个半径为2.5*rg的圆形区块，其中心位于0.5°x0.5°的水平网格上。潮汐流速（来自TPXO9.1；Egbert和Erofeeva，2002年），层结（来自Gouretski和Koltermann，2004年）以及因此波数和相速度，以及地形（SRTM30+；Becker等，2009年）从整个区块对fphi和conv的估算值贡献于各自的区块中心。c）应用于每个区块中高分辨率地形（SRTM30+）上的二维高斯衰减的标准差rg，以确保在区块边界向区块平均值的平滑下降。d）基于SRTM30+的底部深度。e）基于Harris等，2014年的地貌数据，以0.5°和1/120°分辨率排除陡峭的陆坡和浅滩、深海沟和浅海的掩码，用于计算。