Hurricane‐generated currents on the outer continental shelf: 1. Model formulation and verification
Hurricane‐generated currents on the outer continental shelf: 1. Model formulation and verification
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DOI：
10.1029/jc094ic09p12513
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发表时间：
1989-09
影响因子：
--
通讯作者：
C. Cooper;J. Thompson
中科院分区：
文献类型：
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作者：
C. Cooper;J. Thompson
建立了一个数值模式，以模拟飓风在外大陆架和陆坡上产生的海流。重点是在风暴通过的几个小时内的混合层的响应，但是，一些注意力被给予较低的层和货架波的响应。该模型是基于一个分层的，明确的，有限差分公式，使用非线性原始方程，包括热量守恒。地形相交的模型层的问题是通过引入人工步骤的顺序为100米的层相交的斜坡。使用0.2°网格对三场墨西哥湾飓风进行了模式比较。对于两个风暴，该模型再现了超过80%的观测到的速度方差的相关系数大于0.8的混合层。在比较中的差异被追溯到未解决的局部地形和非风暴强迫，如暖芯环。进一步的模式模拟显示：（1）产生了大量的陆棚波，相速度为4至10 m s-1，（2）即使在200 m的浅水中，响应也主要是斜压的，（3）与混合层和上部温跃层之间的速度差成比例的卷吸定律比与风应力成比例的卷吸定律产生了明显更好的比较，和（4）偏离直线风暴路径可以显著改变响应。
A numerical model is developed to simulate currents generated by hurricanes on the outer continental shelf and slope. Emphasis is on the mixed-layer response within a few hours of storm passage; however, some attention is given to the lower layer and shelf wave responses. The model is based on a layered, explicit, finite difference formulation using the nonlinear primitive equations including conservation of heat. The problem of topography intersecting the model layer is resolved by introducing artificial steps of the order of 100 m where the layer intersects the slope. Model comparisons are presented for three Gulf of Mexico hurricanes using a 0.2° grid. For two of the storms, the model reproduces better than 80% of the observed velocity variance with correlation coefficients of greater than 0.8 for the mixed layer. Discrepancies in the comparisons are traced to unresolved local topography and nonstorm forcing such as warm-core rings. Further model simulations reveal that (1) substantial shelf waves were generated with phase speeds of 4 to 10 m s−1, (2) the response is primarily baroclinic even in water as shallow as 200 m, (3) an entrainment law which scales with the velocity difference between the mixed layer and upper thermocline yields markedly better comparisons than one which scales with the wind stress, and (4) deviations from a straight-line storm path can significantly alter the response.