Study Of Acoustic Tomography Of The East China Sea Pn Section In The Kuroshio Region

Sound speed and current velocity of the Kuroshio at the PN section hi East ChinaSea are inverted by using the least square method and singular value decompositiontechnique. Temperature can be calculated easily due to approximately linear relationbetween sound speed and temperature. Hence, heat transport can be obtained. Theconteats of this paper covers:1) Sound speed profiles calculated from CTD datum of the Kuroshio at the PN section in East China Sea decrease with depth. Sound speed in the surface layer varies evidently with seasons. Range difference of sound speed is great and complicated. Approximately linear relation between sound speed and temperature in concerned zone isT = (C-1472) / 2.52.That the Kuroshio flowing along the vertical direction of PN section is approved byanalyzing current datum from LADCP.2) BELLHOP model is improved to simulating acoustic transmission in concerned zone. Simulation shows that the contribution of ray path change to the travel time is. higher than that of sound speed change in some cases. Seabed fluctuation affects on transmission range with increase of surface reflection and bottom reflection. The characteristics of transmission from shallow water zone to deep water zone and contrary are studied. Effect of range variety of sound speed on acoustic transmission is intricate, and changes with depth of sound source.3) Equations of sound speed inversion are introduced. Sound speed is inverted by using the least square method and singular value decomposition technique. Inverse examples of sound speed in spring are given and influence of multi-path signals and depth of sound source is analyzed.4) Scenario of current inverse is designed base on the research object and current characteristics in this zone. Winter currents are inverted and the study shows thatmulti-path signals, angle between two receivers and depth of sound source affect the inverse result.