Brian Dushaw

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We examine statistical and directional properties of the ambient noise in the 10-100 Hz frequency band from the NPAL array. Marginal probability densities are estimated as well as mean square levels, skewness and kurtoses in third octave bands. The kurotoses are markedly different from Gaussian except when only distant shipping is present. Extremal levels(More)
The accuracy of state-of-the-art global barotropic tide models is assessed using bottom pressure data, coastal tide gauges, satellite altimetry, various geodetic data on Antarctic ice shelves, and independent tracked satellite orbit perturbations. Tide models under review include empirical, purely hydrodynamic (" forward "), and assimilative dynamical,(More)
As an aid to understanding long-range acoustic propagation in the Philippine Sea, statistical and phenomenological descriptions of sound-speed variations were developed. Two moorings of oceanographic sensors located in the western Philippine Sea in the spring of 2009 were used to track constant potential-density surfaces (isopycnals) and constant(More)
A series of experiments conducted in the Philippine Sea during 2009-2011 investigated deep-water acoustic propagation and ambient noise in this oceanographically and geologically complex region: (i) the 2009 North Pacific Acoustic Laboratory (NPAL) Pilot Study/Engineering Test, (ii) the 2010-2011 NPAL Philippine Sea Experiment, and (iii) the Ocean Bottom(More)
The analysis of signals for acoustic tomography sent between a source and a receiver most often uses the unrefracted geodesic path, an approximation that is justified from theoretical considerations, relying on estimates of horizontal gradients of sound speed, or on simple theoretical models. To quantify the effects of horizontal refraction caused by a(More)
– Since it was first proposed in the late 1970s (Munk and Wunsch, 1979, 1982), ocean acoustic tomography has evolved into a multipurpose remote-sensing measurement technique that has been employed in a wide variety of physical settings. In the context of long-term oceanic climate change, acoustic tomography provides integrals through the mesoscale and other(More)
The ATOC Project has aquired trans-Pacific acoustic data from two acoustic sources: one located on Pioneer Seamount off the coast of California, the other located north of Kauai, Hawaii. Transmissions from these sources are detected by U.S. Navy SOSUS arrays located throughout the North Pacific. The time series of acoustic travel times from the Pioneer(More)
The application of ocean acoustic tomography in Fram Strait requires a careful assessment of the accuracy to which estimates of sound speed from tomography can be converted to estimates of temperature. The Fram Strait environment is turbulent, with warm, salty, northward-flowing North Atlantic water interacting with cold, fresh, southward-flowing Arctic(More)
Acoustic thermometry gives integral measurements of large-scale ocean temperature, providing the spatial low-pass filtering needed to observe small, gyre-scale signals in the presence of much larger, mesoscale noise. Approximately two-year-long time series of temperature have been measured using long-range acoustic transmissions in the Northeast Pacific by(More)