Internal hydraulic jumps and solitons at a shelf break region on the Australian North West Shelf
Internal hydraulic jumps and solitons at a shelf break region on the Australian North West Shelf
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DOI：
10.1029/jc092ic05p05405
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发表时间：
1987-05
影响因子：
--
通讯作者：
P. Holloway
中科院分区：
文献类型：
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作者：
P. Holloway
一个大振幅，向岸传播，半日内潮以前已被观察到在澳大利亚西北大陆架的大陆架断裂区。本文讨论了详细的观测波形的内潮浅滩的陆棚斜坡，附近的陆棚休息。内潮的前缘变陡，形成内水跃。跳跃的属性是很好地描述了一个两层的水跃模型，在该模型中，几乎均匀的背景温度（密度）剖面强烈扭曲的内部潮汐到一个近似的两层分层前一跳。在123米水深的跳跃的高度达到60米，和跳跃的贡献显着的强烈消散的内潮，以前已经观察到在该地区。在一些跳跃之后，观察到周期为20分钟的12个内波包。这些被描述为孤子，并且发现二阶理论（在波振幅中）是必要的来描述波长和相速度。这些波浪在内潮的能量耗散中也起着重要作用。
A large-amplitude, shoreward propagating, semidiurnal internal tide has previously been observed at a shelf break region on the Australian North West Shelf. This paper discusses detailed observations of the wave shape as the internal tide shoals over the shelf slope, near the shelf break. The leading face of the internal tide is seen to steepen and form an internal hydraulic jump. The properties of the jump are well described by a two-layer hydraulic jump model in which the nearly uniform background temperature (density) profile is strongly distorted by the internal tide to an approximately two-layer stratification just before a jump. The height of the jumps reaches 60 m in 123 m water depth, and the jumps contribute significantly to the strong dissipation of the internal tide that has previously been observed in this region. Following some of the jumps, packets of ∼ 12 internal waves of 20 min period are observed. These are described as solitons, and it is found that a second-order theory (in wave amplitude) is necessary to describe the wavelength and phase speed. These waves also play an important role in the energy dissipation of the internal tide.