Theoretical analysis on waveform structures of pulse propagating in shallow water with an ideal thermocline

I.IntroductionDuetospatia1andtemporalvariabilityoftheocean-acousticenvironment,especially,theeffectsofboundaryaswel1asmediumonpropagationofacousticwavesinshal1owwater,theacousticpropagationisextrcmelycomp1icatcd.Multipathtransmissionisthebasiccharacteris-hcsofunderwatersoundchannels.Undctcrminedmultipathstructurescangreatlylimittheperformanceofunderwateracousticdetcction.However,ifthemultipathcharacteristicsofacousticpropagationinunderwatcrsoundchanne1sareknown,spaee-timeresolutionandpro-cess…

Theoretical analysis on waveform structures of pulse propagating in shallow water with an ideal thermocline

In this paper, waveforms of band-limited signals are calculated under the assumptionof ideal thermocline by using the ray-mode theory with beam displacement (RMB). Comparison between the RMB approach and MOATL codes shows that the RMB approach is a fast and accurate one and the run time by the RMB approach is reduced by at least two orders of magnitude. Results reveal that the beam displacement plays a key role in waveform calculation under the condition of thermocline, and the validity on the formula of mode attenuation coefficient with beam displacement is further proved. The -dependencies of waveforms of pulse signals on source-receiver depths, transmission range, signal frequency, and bottom parameters are discussed.