Acoustic mode coupling due to subaqueous sand dunes in the South China Sea.
The large subaqueous sand dunes on the upper continental slope of the South China Sea are expected to couple acoustic propagating normal modes. In this letter, the criterion of adiabatic invariance is extended to the case of a waveguide possessing bedforms. Using the extended criterion to examine mode propagation over the bedforms observed in the sand dune field in 2012, results demonstrate that bedforms increase mode coupling strength such that the criterion for adiabatic propagation is exceeded for waveguides with small bedform amplitude to water depth ratios; increasing bedform amplitude enhances mode coupling. Numerical simulations confirm the extended criterion parameterization.
Institute of Applied Marine Physics and Undersea Technology, National Sun Yat-sen University, No. 70, Lienhai Road, Kaohsiung, 80424, Taiwan. linus@mail.nsysu.edu.tw
Linus Y S
LY
Chiu
D Benjamin
DB
Reeder
D000162:Acoustics; D003198:Computer Simulation; D019015:Geologic Sediments; D008962:Models, Theoretical; D009038:Motion; D009716:Numerical Analysis, Computer-Assisted; D009792:Oceans and Seas; D012815:Signal Processing, Computer-Assisted; D012822:Silicon Dioxide; D013016:Sound; D013018:Sound Spectrography; D013997:Time Factors; D014867:Water
D014867:Water; D012822:Silicon Dioxide