A fast field model for three‐dimensional wave propagation in stratified environments based on the global matrix method

A three‐dimensional fast field program (FFP) model based on the global matrix method will be presented. Compared to traditional propagator matrix methods, the global matrix method allows for a more efficient, and, furthermore, numerically stable computation. The three‐dimensional expansion does not restrict sources to be on the center axis, but allows for an arbitrary source geometry—as opposed to earlier two‐dimensional versions. As a consequence, the solution includes simultaneously both vertically and horizontally polarized shear waves. A mathematical description will be given and the numerical aspects will be discussed. Some of the features of the model will be illustrated in two test cases: free‐space and shallow water with strongly reflecting bottom. The free‐space case shows that the three‐dimensional solution gives results identical to those obtained by the two‐dimensional model except for ranges close to the axis r≡0 of a cylindrical coordinate system. For the shallow water case, the well‐known e...