Structure and stability of wave-theoretic kernels in the ocean

TitleStructure and stability of wave-theoretic kernels in the ocean
Publication TypeJournal Article
Year of Publication2013
AuthorsDzieciuch M.A, Cornuelle BD, Skarsoulis E.K
JournalJournal of the Acoustical Society of America
Volume134
Pagination3318-3331
Date Published2013/10
Type of ArticleArticle
ISBN Number0001-4966
Accession NumberWOS:000330119700080
Keywordsacoustic tomography; equation; fluctuations; long-range propagation; north pacific-ocean; ray chaos; shadow; sound-speed; time sensitivity kernels
Abstract

Wave-theoretic modeling can be applied to obtain travel-time sensitivity kernels (TSKs) representing the amount ray travel times are affected by sound-speed variations anywhere in the medium. This work explores the spatial frequency content of the TSK compared to expected ocean variability. It also examines the stability of the TSK in environments that produce strong sensitivity of ray paths to initial conditions. The conclusion is that the linear TSK model is an effective predictor of travel-time changes and that the rays perform nearly as well as the full-wave kernel. The TSK is examined in physical space and in wavenumber space, and it is found that this is the key to understanding how the travel time reacts to ocean perturbations. There are minimum vertical and horizontal length scales of ocean perturbations that are required for the travel time to be affected. The result is that the correspondence between true travel times and those calculated from the kernel is high for large-scale perturbations and somewhat less for the small scales. This demonstrates the validity of ray-based inversion of travel time observations for the cases under study. (C) 2013 Acoustical Society of America.

DOI10.1121/1.4818846
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