3aUW11. Stochastic ray theory, chaos, and predictability.

Session: Wednesday Morning, June 18

Author: Michael G. Brown
Location: RSMAS-AMP, Univ. of Miami, 4600 Rickenbacker Cswy., Miami, FL 33149


The motion of sound ray trajectories in deep ocean environments is considered, assuming that the internal wave-induced sound speed fluctuations can be treated stochastically. The ray equations then constitute a system of stochastic differential (Langevin) equations. Equivalently, the expected ray density---an approximation to the average acoustic intensity---can be shown to satisfy a Fokker--Planck equation. The Fokker--Planck equation can be interpreted in fluid mechanical terms as an advection-diffusion equation. This observation leads to the notion of a diffusion-limited (as opposed to diffraction-limited) estimate of the chaos-induced ``predictability horizon.'' [Work supported by ONR.]

ASA 133rd meeting - Penn State, June 1997