Estimation of baroclinic tide energy available for deep ocean mixing based on three-dimensional global numerical simulations
Estimation of baroclinic tide energy available for deep ocean mixing based on three-dimensional global numerical simulations
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DOI：
10.1007/s10872-011-0052-1
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发表时间：
2011-08-01
影响因子：
2.3
通讯作者：
Hibiya, Toshiyuki
中科院分区：
文献类型：
--
作者：
Niwa, Yoshihiro;Hibiya, Toshiyuki
本文利用一个静力σ坐标数值模式研究了全球主要半日（M-2和S-2）和全日（K-1和O-1）斜压潮汐能量的分布。采用1/15-1/5A度的不同水平网格间距进行的一系列数值模拟表明，能量斜压潮汐的产生仅限于具有代表性的显著地形特征。例如，近一半的昼夜（K-1和O-1）斜压潮汐能量被激发沿着北太平洋的西边界从阿留申群岛到印度尼西亚群岛。研究还发现，正压潮汐到斜压潮汐的能量转换率对水平网格间距和模式海底地形分辨率非常敏感，随着模式网格间距的减小，全球海洋的能量转换率呈指数增长。外推计算结果的限制，零网格间距产生的全球转换率估计为1105 GW（821，145，102，53 GW的M-2，S-2，K-1和O-1潮汐分潮，分别）。特别地，在1000米深度以下的开阔海洋中耗散的斜压潮汐能量的量估计为500-600 GW，这与Webb和Suginohara（Nature 409：37，2001）估计的维持全球翻转环流所需的混合能量相当。
The global distributions of the major semidiurnal (M-2 and S-2) and diurnal (K-1 and O-1) baroclinic tide energy are investigated using a hydrostatic sigma-coordinate numerical model. A series of numerical simulations using various horizontal grid spacings of 1/15-1/5A degrees shows that generation of energetic baroclinic tides is restricted over representative prominent topographic features. For example, nearly half of the diurnal (K-1 and O-1) baroclinic tide energy is excited along the western boundary of the North Pacific from the Aleutian Islands down to the Indonesian Archipelago. It is also found that the rate of energy conversion from the barotropic to baroclinic tides is very sensitive to the horizontal grid spacing as well as the resolution of the model bottom topography; the conversion rate integrated over the global ocean increases exponentially as the model grid spacing is reduced. Extrapolating the calculated results in the limit of zero grid spacing yields the estimate of the global conversion rate to be 1105 GW (821, 145, 102, 53 GW for M-2, S-2, K-1, and O-1 tidal constituents, respectively). The amount of baroclinic tide energy dissipated in the open ocean below a depth of 1000 m, in particular, is estimated to be 500-600 GW, which is comparable to the mixing energy estimated by Webb and Suginohara (Nature 409:37, 2001) as needed to sustain the global overturning circulation.