Comparison with KRAKEN

The discussion presented in [11,12] and [1] share in common a calculation of transmission loss for canonical Munk profile shown in Fig.7.1. Source frequency is 50 Hz, and the source is located at 1000 m. 51 rays were traced with TRACEO between -14 $\mbox{$^\circ$}\xspace$ and 14 $\mbox{$^\circ$}\xspace$, restricting the ray fan exclusively to waterborne rays (see Fig.7.12). The ray plot indicates the existence of three large shadow zones, two of them (10-50 km and 70-100 km) in the upper part of the waveguide and the other one (40-80 km) in the lower part of it.

Figure 7.12: TRACEO ray trace.

Those rays were used to calculate a curve a transmission loss, for a receiver at 800 m depth. The comparison of TRACEO with Bellhop and KRAKEN (see Fig.7.13) reveals a good agreement in the general trend of transmission loss calculated by both models. The differences in amplitude are negligible, except in the shadow zones, where rays contribute poorly to the field.

Figure 7.13: Transmission loss comparison: KRAKEN, solid line and TRACEO, dash-point line.