Now showing items 596-615 of 923

    • Observations of wave orbital scale ripples and a nonequilibrium time-dependent model 

      Traykovski, Peter A. (American Geophysical Union, 2007-06-30)
      Measurements of seafloor ripples under wave-dominated conditions from the LEO15 site and the Martha’s Vineyard coastal observatory were used to develop a time-dependent model for ripple geometry. The measurements consisted ...
    • Observed limiting cases of horizontal field coherence and array performance in a time-varying internal wavefield 

      Collis, Jon M.; Duda, Timothy F.; Lynch, James F.; DeFerrari, Harry A. (Acoustical Society of America, 2008-08-28)
      Using a moored source and horizontal/vertical line array combination, horizontal coherence properties of high signal to noise ratio (>=20 dB) 100–1600 Hz signals have been measured. Internal waves in the area of the ...
    • Ocean acoustical ray-tracing : Software Ray 

      Bowlin, James B.; Spiesberger, John L.; Duda, Timothy F.; Freitag, Lee E. (Woods Hole Oceanographic Institution, 1992-10)
      A new computer program for accurate calculation of acoustic ray paths through a range-varing ocean sound channel has been written. It is based on creating a model of the speed of sound in the ocean, consistent with input ...
    • Ocean Seismic Network Pilot Experiment 

      Stephen, Ralph A.; Spiess, Fred N.; Collins, John A.; Hildebrand, John A.; Orcutt, John A.; Peal, Kenneth R.; Vernon, Frank L.; Wooding, Frank B. (2003-10-31)
      The primary goal of the Ocean Seismic Network Pilot Experiment (OSNPE) was to learn how to make high quality broadband seismic measurements on the ocean bottom in preparation for a permanent ocean seismic network. The ...
    • Ocean sound channel ray path perturbations from internal-wave shear and strain 

      Duda, Timothy F. (Acoustical Society of America, 2005-11)
      The relative importance of internal-wave strain and internal-wave shear on perturbation of acoustic ray trajectories in the ocean is analyzed. Previous estimates based on the Garrett-Munk internal-wave spectral model are ...
    • Oceanographic pursuit : networked control of multiple vehicles tracking dynamic ocean features 

      Reed, Brooks L.; Hover, Franz S. (Elsevier, 2014-05-29)
      We present an integrated framework for joint estimation and pursuit of dynamic features in the ocean, over large spatial scales and with multiple collaborating vehicles relying on limited communications. Our approach uses ...
    • Off-axis effects on the multipulse structure of sperm whale usual clicks with implications for sound production 

      Zimmer, Walter M. X.; Madsen, Peter T.; Teloni, Valeria; Johnson, Mark P.; Tyack, Peter L. (Acoustical Society of America, 2005-11)
      Sperm whales (Physeter macrocephalus) produce multipulsed clicks with their hypertrophied nasal complex. The currently accepted view of the sound generation process is based on the click structure measured directly in front ...
    • On acoustic scattering by a shell-covered seafloor 

      Stanton, Timothy K. (Acoustical Society of America, 2000-08)
      Acoustic scattering by the seafloor is sometimes influenced, if not dominated, by the presence of discrete volumetric objects such as shells. A series of measurements of target strength of a type of benthic shelled animal ...
    • On the acoustic diffraction by the edges of benthic shells 

      Stanton, Timothy K.; Chu, Dezhang (Acoustical Society of America, 2004-07)
      Recent laboratory measurements of acoustic backscattering by individual benthic shells have isolated the edge-diffracted echo from echoes due to the surface of the main body of the shell. The data indicate that the echo ...
    • On the dynamics of the Zanzibar Channel 

      Zavala-Garay, Javier; Theiss, Jurgen; Moulton, Melissa; Walsh, Connor; van Woesik, Robert; Mayorga-Adame, Claudia G.; García-Reyes, Marisol; Mukaka, D. S.; Whilden, Kerri; Shaghude, Y. W. (John Wiley & Sons, 2015-09-12)
      The Zanzibar Channel lies between the mainland of Tanzania and Zanzibar Island in the tropical western Indian Ocean, is about 100 km long, 40 km wide, and 40 m deep, and is essential to local socioeconomic activities. This ...
    • On the echo interference in sound backscattering by densely aggregated targets 

      Gorska, Natalia; Chu, Dezhang (2004-12-01)
      It is important to understand the volume backscattering by dense aggregations of a variety of scattering objects such as bubbles or biological targets. This paper addresses the interference of the echoes from randomly ...
    • On the electromagnetic fields produced by marine frequency domain controlled sources 

      Chave, Alan D. (John Wiley & Sons, 2009-10-14)
      In recent years, marine controlled source electromagnetics (CSEM) has found increasing use in hydrocarbon exploration due to its ability to detect thin resistive zones beneath the seafloor. Although it must be recognized ...
    • On the statistics of magnetotelluric rotational invariants 

      Chave, Alan D. (Oxford University Press on behalf of The Royal Astronomical Society, 2013-10-25)
      The statistical properties of the Swift skew, the phase-sensitive skew and the WAL invariants I1−I7 and Q are examined through analytic derivation of their probability density functions and/or simulation based on a Gaussian ...
    • On the turbulent co-spectrum of two scalars and its effect on acoustic scattering from oceanic turbulence 

      Ross, Tetjana; Garrett, Christopher; Lueck, Rolf (Cambridge University Press, 2004-08-24)
      While acoustic scatter from oceanic turbulence is sensitive to temperature–salinity covariations, there are unfortunately no published measurements of the turbulent temperature–salinity co-spectrum. Several models have ...
    • On whether azimuthal isotropy and alongshelf translational invariance are present in low-frequency acoustic propagation along the New Jersey shelfbreak 

      Lynch, James F.; Emerson, Chris; Abbot, Philip A.; Gawarkiewicz, Glen G.; Newhall, Arthur E.; Lin, Ying-Tsong; Duda, Timothy F. (Acoustical Society of America, 2012-02)
      To understand the issues associated with the presence (or lack) of azimuthal isotropy and horizontal (along isobath) invariance of low-frequency (center frequencies of 600 Hz and 900 Hz) acoustic propagation in a shelfbreak ...
    • Optical disk based acquisition system (ODAS) : description and report following the first deployment during the Prudhoe Bay experiment Spring 1987 (PRUDEX) 

      von der Heydt, Keith (Woods Hole Oceanographic Institution, 1987-11)
      This is a report on the use of one vendor's optical disk system for the archiving of data in the field. Two Optimem 1000 units are part of an acquisition system used by the Arctic acoustics groups at Woods Hole Oceanographic ...
    • Optical tools for ocean monitoring and research 

      Moore, C.; Barnard, A.; Fietzek, P.; Lewis, Marlon R.; Sosik, Heidi M.; White, Sheri N.; Zielinski, Oliver (Copernicus Publications on behalf of the European Geosciences Union, 2009-12-10)
      Requirements for understanding the relationships between ocean color and suspended and dissolved materials within the water column, and a rapidly emerging photonics and materials technology base for performing optical based ...
    • Optimal mode localization in disordered, periodic structures 

      Rajagopal, Gopalkrishna (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1995-02)
      Periodic structures which are slightly disordered undergo dramatic changes in mode shapes such that the responses go from being spatially extended to spatially localized. This phenomenon called mode localization, offers ...
    • Optimal multiple source location via the EM algorithm 

      Feder, Meir; Weinstein, Ehud (Woods Hole Oceanographic Institution, 1986-07)
      A computationally efficient scheme for multiple-source location estimation, based on the Estimate-Maximize (EM) algorithm, is presented. The proposed scheme is optimal in the sense that it converges iteratively to the ...
    • Optimal source localization and tracking using arrays with uncertainties in sensor locations 

      Segal, Mordechai; Weinstein, Ehud (Woods Hole Oceanographic Institution, 1989-08)
      We develop a computationally efficient iterative algorithm for source localization and tracking using active/passive arrays with uncertainties in sensor locations. We suppose that the available data consist of time delay, ...