Now showing items 600-619 of 917

    • 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, ...
    • Optimizing copper spheres for precision calibration of hydroacoustic equipment 

      Foote, Kenneth G. (Acoustical Society of America, 1982-03)
      An operational definition of backscattering cross section is developed for the wideband reception of finite echoes. This is supported by relative measurements on a set of copper spheres by each of four echo sounders operating ...
    • Orientation dependence of broadband acoustic backscattering from live squid 

      Lee, Wu-Jung; Lavery, Andone C.; Stanton, Timothy K. (Acoustical Society of America, 2012-06)
      A controlled laboratory experiment of broadband acoustic backscattering from live squid (Loligo pealeii) was conducted using linear chirp signals (60–103 kHz) with data collected over the full 360° of orientation in the ...
    • Orientation dependence of the acoustic backscatter for elongated zooplankton 

      Johnson, Matthew L. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1993-09)
      The width of the main lobe of the acoustic backscatter directivity pattern of decapod shrimp (Palaemonetes vulgaris) is examined versus acoustic frequency. Using the distorted wave Born approximation (DWBA) and the ...
    • Overview of results from the Asian Seas International Acoustics Experiment in the East China Sea 

      Dahl, Peter H.; Zhang, Renhe; Miller, James H.; Bartek, Louis R.; Peng, Zhauhui; Ramp, Steven R.; Zhou, Ji-Xun; Chiu, Ching-Sang; Lynch, James F.; Simmen, Jeffrey A.; Spindel, Robert C. (IEEE, 2004-10)
      The Asian Seas International Acoustics Experiment (ASIAEX) included two major field programs, one in the South China Sea and the other in the East China Sea (ECS). This paper presents an overview of research results from ...
    • A parallel hypothesis method of autonomous underwater vehicle navigation 

      LaPointe, Cara Elizabeth Grupe (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2009-06)
      This research presents a parallel hypothesis method for autonomous underwater vehicle navigation that enables a vehicle to expand the operating envelope of existing long baseline acoustic navigation systems by incorporating ...
    • Particle fluxes associated with mesoscale eddies in the Sargasso Sea 

      Buesseler, Ken O.; Lamborg, Carl H.; Cai, Pinghe; Escoube, Raphaelle; Johnson, Rodney J.; Pike, Steven M.; Masque, Pere; McGillicuddy, Dennis J.; Verdeny, Elisabet (2007-09-25)
      We examined the impact of a cyclonic eddy and mode-water eddy on particle flux in the Sargasso Sea. The primary method used to quantify flux was based upon measurements of the natural radionuclide, 234Th, and these flux ...
    • Passive acoustic detection of deep-diving beaked whales 

      Zimmer, Walter M. X.; Harwood, John; Tyack, Peter L.; Johnson, Mark P.; Madsen, Peter T. (Acoustical Society of America, 2008-11)
      Beaked whales can remain submerged for an hour or more and are difficult to sight when they come to the surface to breathe. Passive acoustic detection (PAD) not only complements traditional visual-based methods for detecting ...
    • A passive capture latch for ODYSSEY-class AUVs 

      Bowen, Martin F. (Woods Hole Oceanographic Institution, 1998-06-12)
      Under subcontract to the Massachusetts Institute of Techology's (MIT) Sea Grant Autonomous Ocean Sampling Network (AOSN) program, the Woods Hole Oceanographic Institution's Deep Submergence Laboratory (WHOI-DSL) produced ...