WBK Approximation in Sound Propagation studies along the Brazilian Continental Slope

The viability of the study of the acoustic tomography models to identify mesoscales processes is the principal objective of this work. Your importance is verified when you need monitoring great areas of national security interest for exploration, defense, and research with less cost and for a long period. The propagation models of the sound in seawater have been a possible way to establish new methodologies and get good results. Bucker's model for the propagation of sound in water [2] by natural modes was used as the starting point of this project. We optimized Bucker's transcendental equation to allow for the variation of sound speed with climatological profiles and obtained the preferred propagation directions of acoustic energy over long distances. CTD data (Conductivity, Temperature, and Density profilers) from the slope and abyssal zones of two areas of interest was used for analysis. Initial results suggest that it is possible to quantify the vertical transport of acoustic energy from the SOFAR (Sound Fixing and Ranging) channel to near the water surface. This analysis suggests acoustic transport is sensitive to thermo-haline variations, consistent with both the numerical solution of the transcendental equation and the normal modes calculated using the WKB approximation on the average data. In particular, the WKB analysis showed that the preferential direction of sound propagation depends greatly on the vertical sound velocity gradient. Using inversion techniques associated with positron modal time [4], we would like in the future to acquire oceanographic data to validate the climatological models well established in the literature.