Ebook: Ocean Variability & Acoustic Propagation

Fifteen years ago NATO organised a conference entitled 'Ocean Acoustic Modelling'. Many of its participants were again present at this variability workshop. One such participant. in concluding his 1975 paper, quoted the following from a 1972 literature survey: ' ... history presents a sad lack of communications between acousticians and oceanographers' Have we done any better in the last 15 years? We believe so, but only moderately. There is still a massive underdeveloped potential for acousticians and oceanographers to make significant progress together. Currently, the two camps talk together insufficiently even to avoid simple misun­ derstandings. such as those in Table 1. Table 1 Ocsanographic and acoustic jargon (from an idea by Pol/ardi Jargon Oceanographic use Acoustic use dbordB decibar (depth in m) decibel (energy level) PE primitive equations parabolic equations convergence zone converging currents converging rays (downwelling water) (high energy density) front thermohaline front wave, ray or time front speed water current speed sound propagation speed 1 The list goes on.

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Content:
Front Matter....Pages i-xi
Front Matter....Pages 1-1
Deterministic-Stochastic Oceanographic Descriptions for Ocean-Acoustic Experiments....Pages 3-22
Experimental Ocean Acoustic Field Moments Versus Predictions....Pages 23-40
Two Dimensional Acoustical Propagation in a Stratified Shear Flow....Pages 41-55
The Effects of Sound Speed on the Shape of the Ocean Impulse Response....Pages 57-68
The Effect of Seasonal Temperature Fluctuations in the Water Column on Sediment Compressional Wave Speed Profiles in Shallow Water....Pages 69-80
Slice89: A Single Slice Tomography Experiment....Pages 81-86
Marginal Ice Zone Oceanographic Variability and Its Effects on Acoustic Propagation....Pages 87-101
Internal Wave Induced Fluctuations in the Oceanic Density and Sound Speed Fields....Pages 103-118
Gyre-Scale Reciprocal Acoustic Transmissions....Pages 119-134
Summary of Session 1....Pages 135-136
Front Matter....Pages 137-137
Chaos in Underwater Acoustics....Pages 139-160
Impulse Response Analysis of Ocean Acoustic Propagation....Pages 161-172
Dependence of Near - Surface Acoustic Scatter on Wind Speed....Pages 173-186
Nonlinear Effects in Wind-Wave Generation....Pages 187-198
Multichannel Acoustic Reflection Profiling of Ocean Watermass Temperature/Salinity Interfaces....Pages 199-214
Acoustic Variability Due to Internal Waves and Surface Waves in Shallow Water....Pages 215-228
Observations Of Ocean Inhomogeneities....Pages 229-236
The Problem of Creating a Synthetic Aperture in a Non-Isotropic Ocean....Pages 237-250
Prediction of Coastal Ocean Thermal Variability....Pages 251-259
Summary of Session 2....Pages 261-261
Front Matter....Pages 263-263
Treatments of Incoherent Scattering for the Parabolic Equation and ASTRAL Propagation Models....Pages 265-281
Average Sound Intensities in Randomly Varying Sound-Speed Structures....Pages 283-292
Stochastic Ray Tracing in Thermoclines....Pages 293-312
Modeling of sound propagation in a randomly varying ocean by stochastic mode coupling....Pages 313-321
Summary of Session 5....Pages 323-323
Front Matter....Pages 325-325
Radar Altimetry and Acoustic Prediction....Pages 327-342
A Range-Dependent Analysis of Acoustic Transmission Across a Cold Filament in the California Current....Pages 343-358
Acoustic Effects of the Iceland-Faeroe Front....Pages 359-374
Deep Hydrographic Fluctuations in the North-East Atlantic Mediterranean Outflow: Influence on Acoustic Propagation....Pages 375-390
Aspects of Oceanographic Variability Observed from Thermistor Chains on Free-Drifting Buoys....Pages 391-406
Theoretical Determination of the Fractal Dimension of Fluid Parcel Trajectories in Large and Meso-Scale Flows....Pages 407-416
How do eddies modify the stratification of the thermocline ?....Pages 417-431
Three-Dimensional Oceanography and Acoustics....Pages 433-448
Frontal Boundaries and Eddies on the Iceland-Faeroes Ridge....Pages 449-461
Upper Ocean Variability Associated with Fronts....Pages 463-478
Summary of Session 3....Pages 479-481
Front Matter....Pages 483-483
A Mixed-Layer Model for Predicting the Acoustic Structure of Shallow Seas....Pages 485-500
The Use of Coupled Ocean-Acoustic Models in the Design of Naval Forecast Systems....Pages 501-516
The Environmental Acoustic Tactical Support System: Low-Frequency Mesoscale Ocean Feature Environmental Acoustic Results....Pages 517-525
Environmental Focusing and Source Localization in the Ocean....Pages 527-538
Front Matter....Pages 483-483
Refraction of Acoustic Modes in Very Long-Range Transmissions....Pages 539-543
Environmental Sensitivity Studies with an Interfaced Ocean - Acoustics System....Pages 545-559
Simulating Temperature, Salinity and Currents in the Ocean....Pages 561-577
A Numerical Investigation of Semi-Diurnal Fluctuations in Acoustic Intensity at a Shelf Edge....Pages 579-592
Summary of Session 4....Pages 593-595
Back Matter....Pages 597-608

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Content:
Front Matter....Pages i-xi
Front Matter....Pages 1-1
Deterministic-Stochastic Oceanographic Descriptions for Ocean-Acoustic Experiments....Pages 3-22
Experimental Ocean Acoustic Field Moments Versus Predictions....Pages 23-40
Two Dimensional Acoustical Propagation in a Stratified Shear Flow....Pages 41-55
The Effects of Sound Speed on the Shape of the Ocean Impulse Response....Pages 57-68
The Effect of Seasonal Temperature Fluctuations in the Water Column on Sediment Compressional Wave Speed Profiles in Shallow Water....Pages 69-80
Slice89: A Single Slice Tomography Experiment....Pages 81-86
Marginal Ice Zone Oceanographic Variability and Its Effects on Acoustic Propagation....Pages 87-101
Internal Wave Induced Fluctuations in the Oceanic Density and Sound Speed Fields....Pages 103-118
Gyre-Scale Reciprocal Acoustic Transmissions....Pages 119-134
Summary of Session 1....Pages 135-136
Front Matter....Pages 137-137
Chaos in Underwater Acoustics....Pages 139-160
Impulse Response Analysis of Ocean Acoustic Propagation....Pages 161-172
Dependence of Near - Surface Acoustic Scatter on Wind Speed....Pages 173-186
Nonlinear Effects in Wind-Wave Generation....Pages 187-198
Multichannel Acoustic Reflection Profiling of Ocean Watermass Temperature/Salinity Interfaces....Pages 199-214
Acoustic Variability Due to Internal Waves and Surface Waves in Shallow Water....Pages 215-228
Observations Of Ocean Inhomogeneities....Pages 229-236
The Problem of Creating a Synthetic Aperture in a Non-Isotropic Ocean....Pages 237-250
Prediction of Coastal Ocean Thermal Variability....Pages 251-259
Summary of Session 2....Pages 261-261
Front Matter....Pages 263-263
Treatments of Incoherent Scattering for the Parabolic Equation and ASTRAL Propagation Models....Pages 265-281
Average Sound Intensities in Randomly Varying Sound-Speed Structures....Pages 283-292
Stochastic Ray Tracing in Thermoclines....Pages 293-312
Modeling of sound propagation in a randomly varying ocean by stochastic mode coupling....Pages 313-321
Summary of Session 5....Pages 323-323
Front Matter....Pages 325-325
Radar Altimetry and Acoustic Prediction....Pages 327-342
A Range-Dependent Analysis of Acoustic Transmission Across a Cold Filament in the California Current....Pages 343-358
Acoustic Effects of the Iceland-Faeroe Front....Pages 359-374
Deep Hydrographic Fluctuations in the North-East Atlantic Mediterranean Outflow: Influence on Acoustic Propagation....Pages 375-390
Aspects of Oceanographic Variability Observed from Thermistor Chains on Free-Drifting Buoys....Pages 391-406
Theoretical Determination of the Fractal Dimension of Fluid Parcel Trajectories in Large and Meso-Scale Flows....Pages 407-416
How do eddies modify the stratification of the thermocline ?....Pages 417-431
Three-Dimensional Oceanography and Acoustics....Pages 433-448
Frontal Boundaries and Eddies on the Iceland-Faeroes Ridge....Pages 449-461
Upper Ocean Variability Associated with Fronts....Pages 463-478
Summary of Session 3....Pages 479-481
Front Matter....Pages 483-483
A Mixed-Layer Model for Predicting the Acoustic Structure of Shallow Seas....Pages 485-500
The Use of Coupled Ocean-Acoustic Models in the Design of Naval Forecast Systems....Pages 501-516
The Environmental Acoustic Tactical Support System: Low-Frequency Mesoscale Ocean Feature Environmental Acoustic Results....Pages 517-525
Environmental Focusing and Source Localization in the Ocean....Pages 527-538
Front Matter....Pages 483-483
Refraction of Acoustic Modes in Very Long-Range Transmissions....Pages 539-543
Environmental Sensitivity Studies with an Interfaced Ocean - Acoustics System....Pages 545-559
Simulating Temperature, Salinity and Currents in the Ocean....Pages 561-577
A Numerical Investigation of Semi-Diurnal Fluctuations in Acoustic Intensity at a Shelf Edge....Pages 579-592
Summary of Session 4....Pages 593-595
Back Matter....Pages 597-608
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