Now showing items 447-466 of 909

    • K-distribution fading models for Bayesian estimation of an underwater acoustic channel 

      Laferriere, Alison Beth (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2011-02)
      Current underwater acoustic channel estimation techniques generally apply linear MMSE estimation. This approach is optimal in a mean square error sense under the assumption that the impulse response fluctuations are well ...
    • The Kallisti Limnes, carbon dioxide-accumulating subsea pools 

      Camilli, Richard; Nomikou, Paraskevi; Escartin, Javier E.; Ridao, Pere; Mallios, Angelos; Kilias, Stephanos P.; Argyraki, Ariadne; Andreani, Muriel; Ballu, Valerie; Campos, Ricard; Deplus, Christine; Gabsi, Taoufic; Garcia, Rafael; Gracias, Nuno; Hurtos, Natalia; Magi, Lluis; Mevel, Catherine; Moreira, Manuel; Palomeras, Narcis; Pot, Olivier; Ribas, David; Ruzie, Lorraine; Sakellariou, Dimitris (Nature Publishing Group, 2015-07-16)
      Natural CO2 releases from shallow marine hydrothermal vents are assumed to mix into the water column, and not accumulate into stratified seafloor pools. We present newly discovered shallow subsea pools located within the ...
    • Kalman filter estimation of underwater vehicle position and attitude using Doppler velocity aided inertial motion unit 

      Leader, Daniel Eugene (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1994-09)
      This Paper explores the use of an extended Kalman filter to provide real-time estimates of underwater vehicle position and attitude. The types of previously available sensors are detailed including strapdown accelerometers, ...
    • Kinematic evaluation of end effector design 

      Edwards, Gary W. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1992-09)
      The complex, many degree-of-freedom end effectors at the leading edge of technology would be unusable in the sea bottom research environment. Simpler designs are required to provide adequate reliability for subsea ...
    • Laboratory evaluation of laser-induced breakdown spectroscopy (LIBS) as a new in situ chemical sensing technique for the deep ocean 

      Michel, Anna Pauline Miranda (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2007-09)
      Present-day expeditionary oceanography is beginning to shift from a focus on short- term ship and submersible deployments to an ocean observatory mode where long- term temporally-focused studies are feasible. As a result, ...
    • Laboratory measurements of high-frequency, acoustic broadband backscattering from sea ice and crude oil 

      Bassett, Christopher; Lavery, Andone C.; Maksym, Ted; Wilkinson, Jeremy P. (Acoustical Society of America, 2014-12-18)
      Recent decreases in summer sea ice cover are spurring interest in hydrocarbon extraction and shipping in Arctic waters, increasing the risk of an oil spill in ice covered waters. With advances in unmanned vehicle operation, ...
    • Laboratory measurements of the sound generated by breaking waves 

      Loewen, Mark Richard (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1991-12)
      Breaking waves dissipate energy, transfer momentum from the wind to surface currents and breaking enhances the transfer of gas and mass across the air-sea interface. Breaking waves are believed to be the dominant source ...
    • Laboratory observations of double-diffusive convection using high-frequency broadband acoustics 

      Ross, Tetjana; Lavery, Andone C. (2008-09)
      High-frequency broadband (200-300 kHz) acoustic scattering techniques have been used to observe the diffusive regime of double-diffusive convection in the laboratory. Pulse compression signal processing techniques allow ...
    • The landward and seaward mechanisms of fine-sediment transport across intertidal flats in the shallow-water region—A numerical investigation 

      Hsu, Tian-Jian; Chen, Shih-Nan; Ogston, Andrea S. (2011-03-15)
      This study investigates transport of fine sediment across idealized intertidal flats with emphasis on resolving processes at the tidal edge, which is defined as the very shallow region of the land-water interface. We first ...
    • Large-area visually augmented navigation for autonomous underwater vehicles 

      Eustice, Ryan M. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2005-06)
      This thesis describes a vision-based, large-area, simultaneous localization and mapping (SLAM) algorithm that respects the low-overlap imagery constraints typical of autonomous underwater vehicles (AUVs) while exploiting ...
    • Large-eddy simulation of the tidal-cycle variations of an estuarine boundary layer 

      Li, Ming; Radhakrishnan, Senthilkumaran; Piomelli, Ugo; Geyer, W. Rockwell (American Geophysical Union, 2010-08-03)
      The estuarine boundary layer affected by a horizontal density gradient exhibits temporal evolution over a tidal cycle, in a manner similar to the diurnal cycle of the ocean surface mixed layer. A large eddy simulation (LES) ...
    • Larval dispersion along an axially symmetric mid-ocean ridge 

      McGillicuddy, Dennis J.; Lavelle, J. William; Thurnherr, Andreas M.; Kosnyrev, V. K.; Mullineaux, Lauren S. (2009-12-22)
      We investigated planktonic larval transport processes along an axially symmetric mid-ocean ridge with characteristics similar to that of the East Pacific Rise (EPR) segment at 9-10°N. The hydrodynamic basis for this study ...
    • Laser diffraction particle sizing : sampling and inversion 

      Riley, James B. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1987-08-13)
      The inverse problem of obtaining particle size distributions from observations of the angular distribution of near forward scattered light is reexamined. Asymptotic analysis of the forward problem reveals the ...
    • Laser Raman spectroscopy as a technique for identification of seafloor hydrothermal and cold seep minerals 

      White, Sheri N. (2008-11)
      In situ sensors capable of real-time measurements and analyses in the deep ocean are necessary to fulfill the potential created by the development of autonomous, deep-sea platforms such as autonomous and remotely operated ...
    • Lateral circulation and sediment transport driven by axial winds in an idealized, partially mixed estuary 

      Chen, Shih-Nan; Sanford, Lawrence P.; Ralston, David K. (American Geophysical Union, 2009-12-03)
      A 3D hydrodynamic model (ROMS) is used to investigate lateral circulation in a partially mixed estuary driven by axial wind events and to explore the associated transport of sediments. The channel is straight with a ...
    • The LatMix summer campaign : submesoscale stirring in the upper ocean 

      Shcherbina, Andrey Y.; Sundermeyer, Miles A.; Kunze, Eric; D’Asaro, Eric; Badin, Gualtiero; Birch, Daniel; Brunner-Suzuki, Anne-Marie E. G.; Callies, Joern; Cervantes, Brandy T. Kuebel; Claret, Mariona; Concannon, Brian; Early, Jeffrey; Ferrari, Raffaele; Goodman, Louis; Harcourt, Ramsey R.; Klymak, Jody M.; Lee, Craig M.; Lelong, M.-Pascale; Levine, Murray D.; Lien, Ren-Chieh; Mahadevan, Amala; McWilliams, James C.; Molemaker, M. Jeroen; Mukherjee, Sonaljit; Nash, Jonathan D.; Ozgokmen, Tamay M.; Pierce, Stephen D.; Ramachandran, Sanjiv; Samelson, Roger M.; Sanford, Thomas B.; Shearman, R. Kipp; Skyllingstad, Eric D.; Smith, K. Shafer; Tandon, Amit; Taylor, John R.; Terray, Eugene A.; Thomas, Leif N.; Ledwell, James R. (American Meteorological Society, 2015-08)
      Lateral stirring is a basic oceanographic phenomenon affecting the distribution of physical, chemical, and biological fields. Eddy stirring at scales on the order of 100 km (the mesoscale) is fairly well understood and ...
    • Length scale of the finite-amplitude meanders of shelfbreak fronts 

      Zhang, Weifeng G.; Gawarkiewicz, Glen G. (American Meteorological Society, 2015-10)
      Through combining analytical arguments and numerical models, this study investigates the finite-amplitude meanders of shelfbreak fronts characterized by sloping isopycnals outcropping at both the surface and the shelfbreak ...
    • Lidar and pressure measurements of inner-surfzone waves and setup 

      Brodie, Katherine L.; Raubenheimer, Britt; Elgar, Steve; Slocum, R. K.; McNinch, Jesse E. (American Meteorological Society, 2015-10)
      Observations of waves and setup on a steep, sandy beach are used to identify and assess potential applications of spatially dense lidar measurements for studying inner-surf and swash-zone hydrodynamics. There is good ...
    • Linearity of fisheries acoustics, with addition theorems 

      Foote, Kenneth G. (Acoustical Society of America, 1983-06)
      An experiment to verify the basic linearity of fisheries acoustics is described. Herring (Clupea harengus L.) was the subject fish. Acoustic measurements consisted of the echo energy from aggregations of encaged but otherwise ...
    • The load/deflection behavior of pretensioned cable/pulley transmission mechanisms 

      Snow, Edward R. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1993-12)
      Mechanical transmission mechanisms enable a designer to match the abilities (e .g. velocity, torque capacity) of an actuator to the needs of an application. Unfortunately the mechanical limitations of the transmission ...