Mesoscale Eddy Energy Locality in an Idealized Ocean Model
Mesoscale Eddy Energy Locality in an Idealized Ocean Model
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理想化海洋模型中的中尺度涡能量局域性
DOI：
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发表时间：
2013
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通讯作者：
K. S. Smith
中科院分区：
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作者：
I. Grooms;L. Nadeau;K. S. Smith
本文研究了风驱动的两层准地转模式中中尺度涡旋的能量收支。直观地说，涡流能量可以从一个地方产生、耗散和流动;平衡产生和耗散的区域是“局部的”，而输出或输入大量涡流能量的区域是“非局部的”。许多中尺度参数化假设未解决的涡旋的统计表现为本地功能的解决大尺度，和研究，涉及双周期模拟海洋补丁必须假设海洋补丁有当地的能量。本研究在模拟风驱动的涡旋中推导并诊断涡旋能量收支。为了更接近亚网格尺度参数化的思想，作者使用空间滤波器而不是更常见的时间平均值来定义平均值和涡旋。在模拟中，涡流能量收支在几乎一半的区域上是强烈非局部的。特别是，在intergyre区域的涡流失去能量，通过与平均值的相互作用，这种能量损失只能由非局部通量的能量从其他地方的域补偿。这项研究还运行双周期模拟对应的海洋补丁盆地模拟。盆地模拟中海洋斑块的涡动能量水平仅在具有局部涡动能量预算的区域与定期模拟中的水平相匹配。
This paper investigates the energy budget of mesoscale eddies in wind-driven two-layer quasigeostrophic simulations. Intuitively, eddy energy can be generated, dissipated, and fluxed from place to place; regions where the budget balances generation and dissipation are ‘‘local’’ and regions that export or import large amounts of eddy energy are ‘‘nonlocal.’’ Many mesoscale parameterizations assume that statistics of the unresolved eddies behave as local functions of the resolved large scales, and studies that relate doubly periodic simulations to ocean patches must assume that the ocean patches have local energetics. This study derives and diagnoses the eddy energy budget in simulations of wind-driven gyres. To more closely approximate the ideas of subgrid-scale parameterization, the authors define the mean and eddies using a spatial filter rather than the more common time average. The eddy energy budget is strongly nonlocal over nearly half the domain in the simulations. In particular, in the intergyre region the eddies lose energy through interactions with the mean, and this energy loss can only be compensated by nonlocal flux of energy from elsewhere in the domain. This study also runs doubly periodic simulations corresponding to ocean patches from basin simulations. The eddy energy level of ocean patches in the basin simulations matches the level in the periodic simulations only in regions with local eddy energy budgets.