Internal Wave Induced Sub-inertial Currents (IWISC)

风和潮汐通过海洋内部重力波场的能量流动可能会产生深远的影响，甚至会影响深海环流的性质，从而对全球气候波动产生影响。因此，了解这种能量流动的途径不仅仅是地球物理流体动力学中的一项深奥练习。到目前为止，几乎没有证据表明，在开阔的海洋中，能量离开内波波段的一个重要途径可能是通过直接产生非共振、非传播的亚惯性运动。在这项研究中，夏威夷大学的一名研究人员将进一步探索作用于惯性和半日内波的这一过程的观测证据。为简单起见，这个过程被称为“内波感应亚惯性电流”或IWISC。他提出，半日内潮汐(名义上在M2频率)和惯性振荡(在频率f)之间的非线性相互作用导致了这些亚惯性运动的产生，这些运动存在于M2减去f的频率附近。初步的分析模型和原始方程模型的数值模拟支持这一猜想，但需要更多的工作来定义其一般动力学。最重要的是，这种对M2-f相互作用的观测可能预示着一类完整的相互作用的存在，这些相互作用将能量泵出内部波场，进入开阔海洋的亚惯性运动。为了探索这一IWISC现象，将使用历史数据集的分析、原始方程数值模式的模拟和理论分析。这项工作的结果大大影响了对可用于混合深海的内波能量总量的估计。除了这项工作的学术价值，这项研究还将支持一名研究生在他的导师的密切监督下进行大部分拟议的工作。

The flow of energy from the winds and tides through the ocean's internal gravity wave field may have far-reaching consequences, impacting even the qualitative nature of the abyssal ocean's circulation, with attendant implications for global climate fluctuations. Consequently, understanding the pathways of this energy flow is more than just an esoteric exercise in geophysical fluid dynamics. Until now, there has been little evidence for the proposition that an important pathway for energy leaving the internal wave band in the open ocean might be by the direct generation of non-resonant, non-propogating, sub-inertial motions.In this study, a researcher at the University of Hawaii will further explore the observational evidence for such a process acting on inertial and semi-diurnal internal waves. For simplicity, the process is referred to as "Internal Wave Induced Sub-inertial Currents" or IWISC. He proposes that a non-linear interaction between the semi-diurnal internal tide (nominally at the M2 frequency) and the inertial oscillations (at frequency f) results in the generation of these sub-inertial motions which exist around the frequency of M2 minus f. Preliminary analytical modeling and numerical simulations with a primitive equation model support this conjecture, but more work is needed to define the dynamics of its generics. Most importantly, this observation of the M2-f interaction may presage the existence of a whole class of interactions that pump energy out of the internal wave field and into sub-inertial motions in the open ocean. To explore this IWISC phenomenon analysis of historical datasets, simulations with a primitive equation numerical model, and theoretical analysis will be used. The results from this work significantly impact the estimates of the mount of internal wave energy that is available for mixing the abyssal ocean. In addition to the intellectual merit of the work, this research will support a graduate student as he conducts much of the proposed work under the close supervision of his advisor.