title: Resolution, identification, and stability of broadband acoustic arrivals in Fram Strait.
abstract: An ocean acoustic tomography system consisting of three moorings with low frequency, broadband transceivers and a moored receiver located approximately in the center of the triangle formed by the transceivers was installed in the central, deep-water part of Fram Strait during 2010-2012. Comparisons of the acoustic receptions with predictions based on hydrographic sections show that the oceanographic conditions in Fram Strait result in complex arrival patterns in which it is difficult to resolve and identify individual arrivals. In addition, the early arrivals are unstable, with the arrival structures changing significantly over time. The stability parameter α suggests that the instability is likely not due to small-scale variability, but rather points toward strong mesoscale variability in the presence of a relatively weak sound channel as being largely responsible. The estimator-correlator [Dzieciuch, J. Acoust. Soc. Am. 136, 2512-2522 (2014)] is shown to provide an objective formalism for generating travel-time series given the complex propagation conditions. Because travel times obtained from the estimator-correlator are not associated with resolved, identified ray arrivals, inverse methods are needed that do not use sampling kernels constructed from geometric ray paths. One possible approach would be to use travel-time sensitivity kernels constructed for the estimator-correlator outputs.
authors.affiliation: Nansen Environmental and Remote Sensing Center, N-5006 Bergen, Norway.
authors.forename: Hanne
authors.initials: H
authors.lastname: Sagen
authors.affiliation: Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093-0225, USA.
authors.forename: Peter F
authors.initials: PF
authors.lastname: Worcester
authors.affiliation: Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093-0225, USA.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Dzieciuch
authors.affiliation: Nansen Environmental and Remote Sensing Center, N-5006 Bergen, Norway.
authors.forename: Florian
authors.initials: F
authors.lastname: Geyer
authors.affiliation: Nansen Environmental and Remote Sensing Center, N-5006 Bergen, Norway.
authors.forename: Stein
authors.initials: S
authors.lastname: Sandven
authors.affiliation: Nansen Environmental and Remote Sensing Center, N-5006 Bergen, Norway.
authors.forename: Mohamed
authors.initials: M
authors.lastname: Babiker
authors.affiliation: Institute of Oceanology of the Polish Academy of Sciences, 81-712 Sopot, Poland.
authors.forename: Agnieszka
authors.initials: A
authors.lastname: Beszczynska-Möller
authors.affiliation: Nansen Environmental and Remote Sensing Center, N-5006 Bergen, Norway.
authors.forename: Brian D
authors.initials: BD
authors.lastname: Dushaw
authors.affiliation: Scripps Institution of Oceanography, University of California at San Diego, La Jolla, California 92093-0225, USA.
authors.forename: Bruce
authors.initials: B
authors.lastname: Cornuelle