Model experiments on sound propagation in the Southwestern Atlantic ocean.

The main goal of this work is to estimate the feasibility of the application of remote acoustic methods to make acoustic tomography in the Southwestern Atlantic Ocean. Trying to reach the best resolution, we searched the optimal location of the emission-reception systems. This work presents the results of a series of numerical simulations made by using a ray model and a Levitus Regional Seasonal Climatology. To optimize the place of the emission-reception system, simulation was carried out along a transect at 40(0) W and 21degrees 30' S -59degrees 30' S. These simulations were made for each season trying to find eigenrays which are stable through the whole year and searching for the best system's response due to temperature changes. The different arriving times of stable eigenrays were calculated for each season. Resulting differences were compared with differences of the average temperatures along the path of each ray, in order to obtain the sensitivity of the system. Attending the necessary commitment between sensitivity and stability we found that the zones with the highest number of stable eigenrays and the appropriate sensitivity for the emission-reception system are: Zone I: between 59degrees 30' S and 57degrees 30' S. Zone II: between 35degrees 30' S and 33degrees S. Inside Zone I the sensitivity was about 350-400 milliseconds per degree of temperature, since inside Zone II the sensitivity was about 600-800 milliseconds per degree.