A way to calculate the amplitude of internal tide and the energy transfer from surface tide to internal tide
Abstract
The generation of internal tides is closely related to surface tides and during the generation process, surface tides somehow give up energy to internal tides. It is important to know the rate at which this energy transfer occurs. This study mainly focuses on the calculations of internal tide's amplitude and on that of internal tide energy. Suppose the stratified ocean has only one pycnocline when internal tides are generated and then, simplify the stratified ocean to an equivalent spring mass system with damp. Subsequently, the surface tide of a certain frequency is taken as external excitation while the internal tide as the system's response to the excitation. When the external excitation is represented as a kind of simple harmonic vibration, the stable response of the above system should be a forced vibration with the same frequency as that of the excitation. Finally, a formula of calculating the system's response or the amplitude of the internal tide is derived by applying the forced vibration theory to the equivalent system. The energy of the internal tide and the energy transfer rate from surface tide to internal tide can also be obtained by further calculations. The analysis show that the amplitude of internal tide and also the energy transfer rate from surface tide to internal tide are dependent on the frequency, the amplitude and the amplitude's vertical distribution of the surface tide. In addition to that, the amplitude of internal tide and the transfer rate are also closely related to the stratification parameters (such as the depth,the thickness and the strength of the pycnocline) and the damping effect of the ocean water. The later extension of this study will be applied to the stratified ocean with more than one pycnoclines.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2018
- Bibcode:
- 2018AGUFMOS31D1802D
- Keywords:
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- 4217 Coastal processes;
- OCEANOGRAPHY: GENERAL