The Mechanism of Internal Tide Generation over Weak Topography

Here the process of internal tide generation over idealized (sinusoidal) topography was investigated using numerical techniques, in which the barotropic-to-baroclinic energy conversion was discussed. The result shows that when the wavenumber of the sinusoidal topography, ktopo, is equal to the horizontal wavenumber of the m-th baroclinic mode km, the conversion from the barotropic tide to the m-th baroclinic mode is enhanced with the increase of topography length; When the wavenumber of the sinusoidal topography is not equal to horizontal wavenumbers of any baroclinic modes, ktopo≠km(m=1,2,...), conversion from the barotropic energy to baroclinic modes is decreased with the increase of topography length. Furthermore, it shows that in resonance case, the phase of the perturbation pressure gradually agrees with the phase of the truncated sinusoidal topography, and the conversion rate is always positive over the topography, thus the baroclinic mode which matches with the wavenumber of the sinusoidal topography persists in absorbing energy from the barotropic tide, and the conversion rate is increased.