Collaborative Research: Quantifying the Kinetic Energy Pathways to Dissipation in the World Ocean

合作研究：量化世界海洋中的动能消散途径

• 批准号: 0849233
• 负责人: Raffaele Ferrari
• 金额: $ 24.37万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-02-01 至 2013-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0849233&HistoricalAwards=false
• 关键词: Collaborative; Research; Quantifying; Kinetic; Energy

The ocean circulation is the result of a balance between forcing at basin scales and dissipation at millimeter scales. While we have measurements of the climatological mechanical and thermal energy sources, and some limited coverage of small-scale dissipation, much less is known about the processes that transfer energy from the forcing to the dissipation scales. The goal of this project is to quantify from observations and numerical models the major pathways towards dissipation in the global oceans. The analysis will be global, but particular attention will be paid to the Southern Ocean, because most of the large scale wind forcing powers this part of the ocean and the resulting currents play a key role in driving the meridional overturning circulation. It is widely believed that most of the wind power input to the surface geostrophic flow drives the large reservoir of available potential energy of the large-scale mean flow, and that this energy is released by baroclinic instability, driving mesoscale eddy kinetic energy (EKE). How this energy is dissipated is much more controversial. The hypotheses to be tested are: 1) A majority of the EKE cascades to the bottom of the ocean through an inverse cascade into larger horizontal scale barotropic motions. 2) A large fraction of this energy flux is dissipated in the bottom boundary layer by quadratic drag. 3) A significant residual energy flux generates topographic waves over rough topography, which have the potential to propagate and upon breaking to drive mixing and dissipation higher in the water column. A combination of satellite and in situ observations, and two realistic, high-resolution ocean general circulation models (OGCMs) will be used. Quantifying the relative importance of the many pathways to dissipation is a great unsolved problem of physical oceanography. Knowing the mechanisms of energy dissipation is a necessary first step in proper parameterization of diapycnal and along isopycnal mixing processes in more realistic OGCMs. Mixing is a critical oceanic process that must be parameterized in order to have the proper feedbacks operative in state-of-the-art models that simulate present and future climate. Together these results will be crucial for guiding future research on the variability and predictability of the global oceans and the climate that it influences.

海洋循环是在盆地尺度强迫与毫米尺度耗散之间平衡的结果。尽管我们对气候机械和热能源进行了测量，并且对小规模耗散的覆盖范围有限，但对将能量从强迫转移到耗散量表的过程的了解少得多。该项目的目的是从观察和数值模型中量化全球海洋耗散的主要途径。该分析将是全球性的，但是将特别关注南大洋，因为大规模的大规模风力强力这一部分和由此产生的电流在推动子午倾覆的循环方面起着关键作用。人们普遍认为，大多数风能输入地面地质流动驱动了大型平均流量的可用势能的大型储层，并且这种能量是由斜压不稳定性释放的，驱动中尺度的涡流动能（EKE）。如何消散这种能量更有争议。要测试的假设是：1）大多数EKE级联反向级联到较大的水平尺度的正压运动。 2）通过二次阻力在底部边界层中消散了很大一部分能量通量。 3）显着的残留能通量会在粗糙的地形上产生地形波，这些图具有传播和破裂后的潜力，以驱动水柱中的混合和耗散。将使用卫星和原位观测以及两个现实的高分辨率海洋循环模型（OGCM）的结合。量化许多耗散途径的相对重要性是物理海洋学的一个很大的未解决问题。了解耗能的机制是对更现实的OGCM中二比和等射体混合过程的正确参数化的必要第一步。混合是一个关键的海洋过程，必须对其进行参数化，以便在模拟当前和将来气候的最先进模型中具有适当的反馈作用。这些结果在一起对于指导对全球海洋的可变性和可预测性的未来研究以及它影响的气候至关重要。