Abstract The spatial and temporal variability of tidal mixing in Bohai Sea is studied using a numerical approach. In calculating tidal mixing, accurate barotropic tidal current is obtained via a harmonic analysis package utilizing the simulated current output from a high-resolution regional ocean model. And a “small-scale” roughness map is adopted to describe the detailed topographic features of Bohai Sea. It is shown that the tidal mixing estimated in Bohai Sea is much higher than the level of global background, and fluctuates considerably at some regions within a single day. In Liaodong Bay, Bohai Bay and Bohai Strait, the mixing varies greatly, with the peak value of O (10−2) m2 s−1. The order of magnitude of mixing in Laizhou Bay is about O (10−5∼10−3) m2 s−1. Mixing with background level of O (10−5) m2 s−1 only appears in central area. Result also shows that rough topography plays relatively a more important role than tidal current in enhancing diapycnal mixing in Bohai Sea. The distributions of tidal mixing in selected sections reveal that the vertical stratification in Bohai Sea is not obvious, generally renders a barotropic structure.

中文翻译：

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渤海潮汐混合数值研究

摘要 利用数值方法研究了渤海潮汐混合的时空变化。在计算潮汐混合时，利用高分辨率区域海洋模型的模​​拟海流输出，通过谐波分析包获得准确的正压潮汐流。并采用“小比例尺”粗糙度图来描述渤海的详细地形特征。结果表明，渤海地区估计的潮汐混合远高于全球背景水平，并且在一天内部分地区波动较大。在辽东湾、渤海湾和渤海海峡，混合变化很大，峰值为O(10−2) m2 s−1。莱州湾的混合量级约为O(10-5∼10-3) m2 s-1。与 O (10−5) m2 s−1 的背景水平混合仅出现在中心区域。结果还表明，在渤海海域，粗糙地形比潮汐流对增强环流混合的作用更为重要。选段潮汐混合分布表明渤海垂直分层不明显，总体呈正压结构。