Effect of Ocean Interannual Variability on Acoustic Propagation in the Philippine Sea and South China Sea
NAVAL POSTGRADUATE SCHOOL MONTEREY CA MONTEREY United States
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Effect of interannual variability of temperature and salinity on acoustic propagation in the Philippine Sea and South China Sea is investigated using the Navys climatological T, S dataset i.e., Generalized Digital Environmental Model GDEM and the Synoptic Monthly Gridded World Ocean Database SMGWODdata from January 1960 to December 2014, and an open source acoustic model BELLHOP. The multi-year averaged monthly T, S profiles calculated from the SMG-WOD agree quite well with the GDEM with slight difference in upper layers, especially in thermoclines. The interannual variability of the transmission loss TL is identified using the BELLHOP model with the sound speed profiles calculated from the SMG-WOD and GDEM. Less TL was found in the convergence paths modelled from the SMGWOD. Interannual 3-7 years variabilities were found in each decade. The TL does not show strong interannual variabilities over the convergence paths however, the interannual variability will affect the TL between the convergence paths, in the formation of surface duct, sound channels and bottom bounce. The SMG-WOD data is more suitable to assess the interannual variability effect on the acoustic propagation.
- Physical and Dynamic Oceanography