Arrival-time perturbations of broadband tomographic signals due to sound- speed disturbances. A wave-theoretic approach

Athanassoulis, GA; Skarsoulis, EK

dc.contributor.author	Athanassoulis, GA	en
dc.contributor.author	Skarsoulis, EK	en
dc.date.accessioned	2014-03-01T01:10:49Z
dc.date.available	2014-03-01T01:10:49Z
dc.date.issued	1995	en
dc.identifier.issn	0001-4966	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/11459
dc.subject.classification	Acoustics	en
dc.subject.other	acoustics	en
dc.subject.other	article	en
dc.subject.other	correlation function	en
dc.subject.other	environment	en
dc.subject.other	linear system	en
dc.subject.other	priority journal	en
dc.subject.other	sea	en
dc.subject.other	sound transmission	en
dc.subject.other	tomography	en
dc.subject.other	waveform	en
dc.title	Arrival-time perturbations of broadband tomographic signals due to sound- speed disturbances. A wave-theoretic approach	en
heal.type	journalArticle	en
heal.identifier.primary	10.1121/1.412441	en
heal.identifier.secondary	http://dx.doi.org/10.1121/1.412441	en
heal.language	English	en
heal.publicationDate	1995	en
heal.abstract	The problem of arrival-time perturbations due to perturbations of the sound-speed profile is studied on the basis of full-wave equation modeling of the direct problem. Arrival times are analytically modeled as the time instants corresponding to the significant maxima (peaks) of the arrival pattern, in full agreement with measurement practice. In this framework the identification of actual (measured) arrivals as ray or modal ones is not required. An elegant perturbation formula is derived for the arrival times, containing the background arrival times, time derivatives of quantities associated with the background field, and also the functional derivative of the background field with respect to the sound-speed profile. This formula is of a system-theoretic nature and can be applied to any kind of environment, either range-dependent or range-independent. The restriction to the range- independent environment permits further elaboration of the perturbation formula since, in this case, the functional derivative of the acoustic- channel transfer function can be analytically expressed, e.g., in terms of normal modes. The performance of the proposed approach is demonstrated by studying two test cases: the linear- and the canonical-profile waveguide. The agreement between actual arrival times, obtained by numerically solving the direct propagation problem, and the arrival times predicted by means of the perturbation formula is very satisfactory. Since the proposed scheme can predict arrival-time perturbations even in cases that the arrival times cannot be identified as ray or modal ones, it is expected to be helpful in extending the applicability of ocean acoustic tomography.	en
heal.publisher	AMER INST PHYSICS	en
heal.journalName	Journal of the Acoustical Society of America	en
dc.identifier.doi	10.1121/1.412441	en
dc.identifier.isi	ISI:A1995RD45300012	en
dc.identifier.volume	97	en
dc.identifier.issue	6	en
dc.identifier.spage	3575	en
dc.identifier.epage	3588	en