Out-of-plane effects in three-dimensional oceans

The two-dimensional beam tracing algorithms in the BELLHOP acoustic model have been extended to three dimensions in BELLHOP3D. The new model includes virtually all of the capabilities of the 2D model, including 1) spatially varying bottom-types, 2) eigenray calculations, 3) TL calculations, and 4) time series calculations. In addition, the 3D model includes both the geometric and Gaussian beam tracing options. Finally, a simple option change allows it to switch between 2D and 3D calculations to assess the effects of horizontal refraction. This talk will discuss the algorithm, demonstrate its capabilities, and present results that illustrate when horizontal refraction is important.