An intercomparison of low‐level signal detectability in a shallow water environment using horizontal, vertical, and tilted vertical arrays

1997 ◽  
Vol 101 (5) ◽  
pp. 3047-3047 ◽  
Author(s):  
W. S. Hodgkiss ◽  
J. J. Murray ◽  
N. O. Booth ◽  
P. W. Schey
Keyword(s):  
Shallow Water ◽  
Water Environment ◽  
Low Level ◽  
Vertical Arrays ◽  
Shallow Water Environment ◽  
Signal Detectability

MODE AND WAVENUMBER INVERSION IN SHALLOW WATER USING AN ADJOINT METHOD

2004 ◽  
Vol 12 (04) ◽  
pp. 521-542 ◽  
Author(s):  
ISABELLE CHARPENTIER ◽  
PHILIPPE ROUX
Keyword(s):  
Shallow Water ◽  
Adjoint Method ◽  
Automatic Differentiation ◽  
Pressure Field ◽  
Water Environment ◽  
Specific Treatment ◽  
Oceanic Waveguide ◽  
New Approach ◽  
Vertical Arrays ◽  
Shallow Water Environment

Modes and wavenumbers are the principal ingredients that characterize the pressure field in an oceanic waveguide. However, wavenumber and mode inversions are well-known to be a difficult task in underwater acoustics. Moreover, this double inversion has never been performed simultaneously from the same configuration of emitters and receivers. We present a new approach to this problem in a shallow water environment between two vertical arrays of sources and receivers. Starting from a classical modal decomposition of the pressure field, our algorithm focuses on a specific treatment of phase and amplitude variables. The key idea is to run a three-stage optimization by working separately on the phase and amplitude of the acoustic field. The high number of variables of the problem is turned into an advantage by using an adjoint code generated by an Automatic Differentiation software. Numerical results in the presence of noise show that modes and wavenumbers are estimated with a high accuracy.

Hawaii Experimental Acoustics Range for Shallow Water Applications

2011 ◽  
Vol 45 (3) ◽  
pp. 69-76 ◽  
Author(s):  
Tom Fedenczuk ◽  
Eva-Marie Nosal
Keyword(s):  
Shallow Water ◽  
Water Environment ◽  
Shallow Water Acoustics ◽  
Central Node ◽  
Long Baseline ◽  
Wide Range ◽  
Shallow Water Environment ◽  
Near Shore ◽  
Monitoring And Surveillance ◽  
Passive Acoustic

AbstractShallow water acoustics provide a means for monitoring and surveillance of near-shore environments. This paper describes the current and future capabilities of the low- to high-frequency Hawaii Experimental Acoustics Range (HEAR) that was designed to facilitate a wide range of different shallow water acoustics experiments and allow researchers from various institutions to test various array components and configurations. HEAR is a portable facility that consists of multiple hydrophones (12‐16) cabled independently to a common central node. The design allows for variable array configurations and deployments in three modes: experimental (off boats and piers), autonomous, and cabled. An application of HEAR is illustrated by the results from a deployment at Makai Research Pier, Oahu, Hawaii. In this deployment, HEAR was configured as a long-baseline range of two volumetric subarrays to study passive acoustic tracking capabilities in a shallow water environment.

scholarly journals Analysis of wind-driven ambient noise in a shallow water environment with a sandy seabed

2008 ◽  
Vol 124 (3) ◽  
pp. EL157-EL162 ◽  
Author(s):  
D. P. Knobles ◽  
S. M. Joshi ◽  
R. D. Gaul ◽  
H. C. Graber ◽  
N. J. Williams
Keyword(s):  
Shallow Water ◽  
Ambient Noise ◽  
Water Environment ◽  
Shallow Water Environment

Aldebarania arenitea, a new genus and species of Astropectinidae (Asteroidea; Echinodermata) from the Maastrichtian (Upper Cretaceous) Peedee Formation of North Carolina

1995 ◽  
Vol 69 (2) ◽  
pp. 376-380 ◽  
Author(s):  
Daniel B. Blake ◽  
Keith Sturgeon
Keyword(s):  
North Carolina ◽  
Shallow Water ◽  
Phylogenetic Relationships ◽  
Upper Cretaceous ◽  
New Genus ◽  
Water Environment ◽  
New Genus And Species ◽  
Marine Fauna ◽  
Shallow Water Environment

Aldebarania arenitea (Astropectinidae; Asteroidea; Echinodermata) is described from the Rocky Point Member of the Maastrichtian (Upper Cretaceous) Peedee Formation of North Carolina. A turbulent, shallow-water environment is suggested by sedimentary features, a diverse marine fauna, and the morphology of Aldebarania. Aldebarania appears to be a partial ecological equivalent of living Astropecten and Luidia; however, phylogenetic relationships within the Astropectinidae are unstudied and the origin of similarities is unknown.

Trilobites from the Ordovician Shihtzupu Formation, Zunyi, Guizhou Province, China

1984 ◽  
Vol 75 (1) ◽  
pp. 13-36 ◽  
Author(s):  
Zhiyi Zhou ◽  
Gongzheng Yin ◽  
Ronald P. Tripp
Keyword(s):  
Shallow Water ◽  
Water Environment ◽  
Guizhou Province ◽  
Type Section ◽  
Shallow Water Environment ◽  
First Time

ABSTRACTTwenty-seven species assigned to 20 genera of trilobites are described from Feilaishi in Guizhou Province, the type section of the Shihtzupu Formation in S W China. They occur in association with a sparse graptolite fauna including Glyptograptus teretiusculus. Eleven taxa are recorded here for the first time. Much new morphological information is provided regarding previously known species and 3 lectotypes are selected. The trilobites are largely endemic and indicate a quiet and comparatively shallow water environment

scholarly journals Passenger ship source level determination in shallow water environment

2016 ◽  
Author(s):  
Mirko Mustonen ◽  
Aleksander Klauson ◽  
Janek Laanearu ◽  
Madis Ratassepp ◽  
Thomas Folegot ◽  
...  
Keyword(s):  
Shallow Water ◽  
Water Environment ◽  
Passenger Ship ◽  
Shallow Water Environment ◽  
Source Level

scholarly journals Wave Equation Datuming Applied to Seismic Data in Shallow Water Environment and Post-Critical Water Bottom Reflection

Energies ◽  
2017 ◽  
Vol 10 (9) ◽  
pp. 1414 ◽  
Author(s):  
Umberta Tinivella ◽  
Michela Giustiniani ◽  
Ivan Vargas-Cordero
Keyword(s):  
Wave Equation ◽  
Shallow Water ◽  
Seismic Data ◽  
Water Environment ◽  
Shallow Water Environment ◽  
Water Bottom
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