Accession Number : AD1046596


Title :   Effect of Ocean Interannual Variability on Acoustic Propagation in the Philippine Sea and South China Sea


Descriptive Note : Technical Report


Corporate Author : NAVAL POSTGRADUATE SCHOOL MONTEREY CA MONTEREY United States


Personal Author(s) : Yudono,Albert M


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/1046596.pdf


Report Date : 01 Jun 2017


Pagination or Media Count : 213


Abstract : 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 (SMGWOD)data 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.


Descriptors :   OCEAN FLOOR , Bathymetry , Acoustic waves , stratification , SALINITY


Subject Categories : Physical and Dynamic Oceanography
      Acoustics


Distribution Statement : APPROVED FOR PUBLIC RELEASE