Towards developing a generalized semi-coherent three-dimensional energy flux model

Abstract

The energy flux method can be interpreted as an integration over propagation angle of a semi-classical (WKB) modal continuum, which yields an averaged incoherent intensity field with depth-dependent intensity bands that decay in range. Range dependence is typically incorporated via the adiabatic modes approximation and use of the ray invariant to map propagation angles. Though the energy flux method averages out nearly all of the field structure, it has the primary advantages of avoiding finding eigenvalues and eigenrays and its computational effort does not directly scale with frequency or range. The method has also been extended in the past decade to include a convergence factor derived from the interference of neighboring modes, producing a semi-coherent solution that captures some convergence structure analogous to high-frequency caustics. Since the development of the semi-coherent energy flux method, it has so far only been applied to Nx2D environmental models, but should theoretically be applicable in a 3D environment without the assumption of azimuthal symmetry or the exclusion of horizontal refraction. This paper will discuss the theoretical derivation and numerical implementation of a generalized semi-coherent three-dimensional energy flux model. [This study is funded by the NDSEG Fellowship program.]