Parametric Subharmonic Instability of the Internal Tide at 29 8 N
Parametric Subharmonic Instability of the Internal Tide at 29 8 N
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发表时间：
2013
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通讯作者：
A. J.;Mackinnon;H. M.;Alford;O. Sun;R. Pinkel;Zhong‐Kuo Zhao;J. Klymak
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作者：
A. J.;Mackinnon;H. M.;Alford;O. Sun;R. Pinkel;Zhong‐Kuo Zhao;J. Klymak
观测证据表明，能量从内潮转移到近惯性运动附近的29 8 N在太平洋。这种转移是通过参数次谐波不稳定性（PSI）实现的，它涉及一个主波（在这种情况下是内潮）和两个频率接近一半的小尺度波之间的相互作用。该位置的内潮是从夏威夷向北传播的低模式波和在当地海山产生的高模式波的复杂叠加，使PSI理论的应用具有挑战性。然而，记录了内潮与向上和向下传播的近惯性波之间的统计学显著相位锁定。这三个波之间的相位与PSI理论的预期一致。计算出的能量传递率从潮汐到近惯性运动是适度的，与当地耗散率估计一致。结论是，虽然PSI确实发生在29 - 8 N的临界纬度附近的潮汐，但它不会造成灾难性的后果。
Observational evidence is presented for transfer of energy from the internal tide to near-inertial motions near 29 8 N in the Pacific Ocean. The transfer is accomplished via parametric subharmonic instability (PSI), which involvesinteractionbetweena primarywave (the internaltide in this case) and two smaller-scale waves of nearly half the frequency. The internal tide at this location is a complex superposition of a low-mode waves propagating north from Hawaii and higher-mode waves generated at local seamounts, making application of PSI theory challenging. Nevertheless, a statistically significant phase locking is documented between the internal tide and upward- and downward-propagating near-inertial waves. The phase between those three waves is consistent with that expected from PSI theory. Calculated energy transfer rates from the tide to near-inertial motions are modest, consistent with local dissipation rate estimates. The conclusion is that while PSI does befall the tide near a critical latitude of 29 8 N, it does not do so catastrophically.