Nonlinear harmonic generation by diurnal tides

作者：Wunsch Scott^*

来源：Dynamics of Atmospheres and Oceans, 2015, 71: 91-97.

DOI：10.1016/j.dynatmoce.2015.06.002

• Diurnal tides
• Harmonics
• Nonlinear internal waves

Recent observations from the South China Sea have demonstrated that semi-diurnal tides sometimes generate a double-frequency harmonic. Similar harmonic generation has been found in laboratory experiments and numerical simulations of internal wave beams refracting into a pycnocline. Here, a weakly nonlinear theory of internal wave refraction is applied to oceanic internal tides in an idealized stratification profile. The steady state harmonic amplitude is calculated as a function of the tidal frequency and the pycnocline characteristics. The results indicate that harmonic generation by nonlinear refraction of semi-diurnal tides is consistent with the South China Sea observations.

• 出版日期2015-9