Dense water formation around islands
Dense water formation around islands
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岛屿周围形成浓水
DOI：
10.1002/jgrc.20185
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发表时间：
2013
影响因子：
--
通讯作者：
M. Spall
中科院分区：
文献类型：
--
作者：
M. Spall
[1]稠密水的形成率和环流的基本限制，导致冷却周围的岛屿进行了讨论。所考虑的区域包括一个被大陆架、大陆坡和分层海洋包围的岛屿。大陆架上的大气冷却形成了一种稠密的水，这种水沿着倾斜的底部渗透到分层的盆地中。由于热成风的作用，在倾斜的底部产生了强烈的方位流。热直接和间接的平均翻转细胞也被迫在斜坡上的收敛和发散的雷诺应力与射流带的结果。与净质量通量相关的科里奥利力进入下降流区域的斜坡是平衡的这些非线性项，从而产生一个根本不同的动量预算比出现在半封闭的边缘海冷却。一个类似的动量平衡的情况下，峡谷和山脊周围的岛屿，条件是考虑在一个坐标系，遵循地形。涡动通量和平均翻转单元对径向热通量都很重要，尽管涡动通量通常占主导地位。斜压不稳定理论和简单的热量和质量收支的应用，很好地预测了密集的水在大陆架上形成的属性（温度，diapycnal质量通量）。结果表明，这些量中的每一个只依赖于一个无量纲的数字来自环境参数，如货架深度，科里奥利参数，近海温度场，和大气强迫。
[1] Basic constraints on the dense water formation rate and circulation resulting from cooling around an island are discussed. The domain under consideration consists of an island surrounded by a shelf, a continental slope, and a stratified ocean. Atmospheric cooling over the shelf forms a dense water that penetrates down the sloping bottom into the stratified basin. Strong azimuthal flows are generated over the sloping bottom as a result of thermal wind. Thermally direct and indirect mean overturning cells are also forced over the slope as a result of bands of convergent and divergent Reynolds stresses associated with the jets. The Coriolis force associated with the net mass flux into the downwelling region over the slope is balanced by these nonlinear terms, giving rise to a fundamentally different momentum budget than arises in semienclosed marginal seas subject to cooling. A similar momentum balance is found for cases with canyons and ridges around the island provided that the terms are considered in a coordinate system that follows the topography. Both eddy fluxes and the mean overturning cells are important for the radial heat flux, although the eddy fluxes typically dominate. The properties of the dense water formed over the shelf (temperature, diapycnal mass flux) are predicted well by application of baroclinic instability theory and simple heat and mass budgets. It is shown that each of these quantities depends only on a nondimensional number derived from environmental parameters such as the shelf depth, Coriolis parameter, offshore temperature field, and atmospheric forcing.