image: Isotherms at ten equally spaced times during 2.5 tidal cycles in the standard numerical experiment. The hollow arrows indicate the directions of the tidal currents, and the small red and blue arrows indicate the westward and eastward propagating ISWs, respectively. The insets in (a) – (c) are local enlargements of the isotherms around sill A. view more
Credit: ©Science China Press
This study is led by Prof. Cai (South China Sea Institute of Oceanology, Chinese Academy of Sciences). The two-dimensional Massachusetts Institute of Technology general circulation model is applied to investigate the dynamics of ISWs in the southern Andaman Sea. From west to east, there are three main ridges along the section of the Great Channel, i.e., the sill of the Great Channel, the Dreadnought Bank and the eastern shallow sill, labelled as sills A, B and C, respectively.
Prof Cai’s team found the large-amplitude depression ISWs are mainly generated via the oscillating semi-diurnal tidal flow over the sill of the Great Channel, and the generation of ISWs is subject to the lee wave regime. The Dreadnought Bank cannot generate ISWs itself; however, it can enhance the amplitudes of eastward-propagating ISWs generated from sill A, owing to constructive interference of internal tide generation between the sill of the Great Channel and the Dreadnought Bank. The eastward-propagating ISWs generated by the eastern shallow sill near the continental shelf can propagate to the shelf, where they evolve into elevation waves because of the shallow water. Sensitivity runs show that both the semidiurnal and diurnal tides over the sill of the Great Channel can generate ISWs in this area. However, the ISWs generated by diurnal tides are much weaker than those generated by semidiurnal tides. Mixed tidal forcing has no significant effect on the generation of ISWs.
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See the article:
On the generation and propagation of internal solitary waves in the southern Andaman Sea: A numerical study
https://doi.org/10.1007/s11430-020-9802-8
Journal
Science China Earth Sciences