Acoustic Sensing Techniques for the Shallow Water Environment: Inversion Methods and Experiments

331 Pages·2006·30.586 MB·English

by  Jean-Claude Le Gac, Yann Steéphan (auth.), Andrea Caiti, N. Ross Chapman, Jean-Pierre Hermand, Sérgio M. Jesus (eds.)

Andrea Caiti
N. Ross Chapman
Jean-Pierre Hermand
Sérgio M. Jesus
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Table of Contents
Preface
Acknowledgements
Ontheassessmentofgeoacousticparametersinshallowwaterenvironments 1
´
Bayesianinversionofseabedreflectiondata 17
Backpropagationtechniquesinoceanacousticinversion: timereversal,retrogation 29
and
MatthiasMeyerandJean PierreHermand
AcousticinversionatlowkHzfrequenciesusinganactive,verticallinearray 47
Dispersionofbroadbandacousticnormalmodesinthecontextoflongrange
sediment tomography 57
GopuPottyandJamesMiller
Characterizationoflocalseabedpropertiesusingsynthesizedhorizontalarraydata 73
PeterL.Nielsen,MarkFallatandChristopherHarrison
Characterizationofarange-dependentenvironmentfromtowedarraydata 87
Accountingforbiasinhorizontalwavenumberestimatesduetosourcemotion 99
KyleM.Becker
Acousticclutterfromburiedsubmarinemudvolcanoes 109
CharlesW.Holland,AnthonyL.GerigandPieroBoni
Nonlinearacousticalmethodsinthedetectionofgassysediments 125
JarosławTTee¸gowski,ZygmuntKlusekandJaromirJakacki
Acousticscatteringfromsubmergedandburiedobjects 137
IlkkaKarasaloandPatrikSkogqvist
High-frequencybistaticscatteringexperimentsusingproudandburiedtargets 155
Asedimentprobefortherapidassessmentofseabedcharacteristics 171
JohnOsler,ArnoldFurlongandHaroldChristian
Continuousacousticmonitoringofphysiologicalandenvironmentalprocesses
inseagrassprairieswithfocusonphotosynthesis 183
Jean-PierreHermand
Shallowwatertomographyinahighlyvariablescenario 197
Inversionsofreflectionlossmeasurementsofasmoothwater/sandinterface 213
Estimationoftransmissionlossanditsuncertainty 233
Aforwardmodelforgeoacousticinversionbasedonraytracingandplane-wave
reflection coefficients 241
JensM.Hovem,HefengDongandXiukunLi
Inversionofthepropellerharmonicsfromalightaircraftforthegeoacoustic
propertiesofmarinesediments 257
Inversionofshallowwaterambientnoisedatabymeansofdifferentialevolution
asa globalsearchmethod 265
DickG.Simons,CamielvanMollandChrisH.Harrison
Reflectionlossandsub-bottomprofilingwithambientnoise 281
ChrisHarrison
Inversionofgeoacousticmodelparametersusingshipradiatednoise 289
,RezaM.Dizajiand R.LynnKirlin
Matched-fieldprocessingofhumpbackwhalesongoffeasternAustralia
.
Inversionsofhorizontalandverticallinearraydatafortheestimationof
geoacoustic modelparameters 309
DagTollefsen,MichaelJ.WilmutandRossChapman
Issues of environmental variability in inverse problems in ocean 321
AuthorIndex
SubjectIndex
Preface
This volume contains the collection of papers from the second workshop on Experi-
mentalAcousticInversionTechniquesforExplorationoftheShallowWaterEnvironment.
Theworkshopthemefollowedtheoriginalconceptofthefirstworkshop,heldinCarvoeiro,
Portugal, in 1999, i.e., to focus on experiments and experimental techniques for acoustic
sensingintheshallowocean. Morethanfortyleadinginternationalscientistswereinvited
to meet in the picturesque town of St. Angelo on the island of Ischia, in June 2004, to
discuss progress in the application of new experimental techniques for exploration and
assessmentofshallowwaterenvironments.
Acoustictechniquesprovidethemosteffectivemeansforremotesensingofoceanand
sea floor processes, and for probing the structure beneath the sea floor. No other energy
propagates as efficiently in the ocean: radio waves and visible light are severely limited
inrangebecausetheoceanisahighlyconductivemedium. However, soundfrombreak-
ingwavesandcoastalshippingcanbeheardthroughouttheocean,andmarinemammals
communicateacousticallyoverbasinscaledistances.
The motivation for developing and improving acoustic techniques for shallow water
applications remains as strong as ever. Near coast and inshore environments worldwide
arecriticallyimportanthabitatsformanyecologically,commercially,andsociallyimpor-
tant species. They are also rich with hydrocarbon and other mineral resources. At the
sametime,theseareashousenearly60%oftheworld’spopulationandgenerateapproxi-
mately25%ofglobalprimaryproductivity. Pressurefromindustrialactivityinthecoastal
cities,developmentofoffshoreresources,internationalandlocalshippingtrafficandeven
recreationcontinuestothreatenthecoastalshallowwaterenvironment.
The papers in this book indicate a high level of research interest that has generated
significant progress in development and application of experimental acoustic inversion
techniques since the last workshop. The applications span a broad scope in geoscience,
fromgeophysical,biologicalandevengeochemicalresearch. Thelistincludes: estimation
of geotechnical properties of sea bed materials; navigation and mapping of the sea floor;
fisheries, aquaculture and sea bed habitat assessment; monitoring of marine mammals;
sedimenttransport;andinvestigationofnaturalgeohazardsinmarinesediments.
Several papers reveal progress in using high frequency acoustic backscatter to image
objects on and beneath the sea floor, and generate data bases that combine bathymetry
withnon-acousticinformationtoprovidecomprehensivehabitatmapsoffeaturessuchas
eelgrass. Anewnonlinearacoustictechniqueisreportedfordetectingandquantifyingthe
amountofgasinshallowmarinesediments.
Significantprogressisreportedinaseriesofpapersrelatedtothedevelopmentofnew
techniques for estimating geoacoustic properties of the sea bed by inversion of acoustic
intheocean,andalsonovelexperimentsthatuseaircraftandshipsasthesoundsource.The
sameinversiontechniquesarealsobeingusedforpassivedetectionandtrackingofmarine
mammals,usinganewautonomousexperimentalrecordingsystem. Acommonfeaturein
alltheinversiontechniquesistheinter-relationshipofdiversefeaturesandprocessesthat