Impact of Littoral Environmental Variability on Acoustic Predictions and Sonar Performance

ISBN-13: 9789401039338 / Angielski / Miękka / 2013 / 620 str.

N.G. Pace;Finn B. Jensen

Opis

The limiting influence of the environment on sonar has long been recognised as a major challenge to science and technology. As the area of interest shifts towards the lit toral, environmental influences become dominant both in time and space. The manyfold challenges encompass prediction, measurement, assessment and adaptive responses to maximize the effectiveness of systems. Although MCM and ASW activities are dom inated in different ways and scales by the environment, both warfare areas have had to consider the significantly changing requirements posed by operations in the littoraL The fundamental scientific issues involved in developing models relating acoustics to the environment are matched in difficulty by the need for data for their validation and eventual practical use for prediction. In many instances the need is for on-line adaptation of systems to changing circumstances whilst other needs are for the Ionger term planning activities. This book and the attached full-color CD are the proceedings of a conference organ ised by the SACLANT Undersea Research Centre, held at Villa Marigola, Lerici, Italy, on 16-20 September 2002. The fundamental problems associated with environmental 1 variability and sonar were explored at a previous SACLANTCEN conference in 1990. These problems have not gone away but, on the one hand are exaggerated by the move to the littoral and on the other hand, are open to treatrnent in new ways that advances in technology and computer power allow."

Spis treści

Preface. Section 1: Ocean variability. Acoustic effects of environmental variability in the SWARM, PRIMER and ASIAEX experiments (Invited paper); J. Lynch, et al. Acoustic intensity variability in a shallow water environment; B.H. Pasewark, et al. Combination of acoustics with high resolution oceanography (Invited paper); J. Sellschopp, et al. Effect of hurricane Michael on the underwater acoustic environment of the Scotian Shelf; D. Hutt, et al. High-frequency acoustic propagation in the presence of oceanographic variability; M. Badiey, et al. Instrumented tow cable measurements of temperature variability of the water column; A.A. Ruffa, M.T. Sundvik. Mesoscale - small scale oceanic variability effects on underwater acoustic signal propagation; E. Coelho. Spatial coherence of signals forward scattered from the sea surface in the East China Sea (Invited paper); P.H. Dahl. Variability in high frequency acoustic backscattering in the water column; A.C. Lavery, et al. Section 2: Seabed variability. Intra- and inter-regional geoacoustic variability in the littoral (Invited paper); C.W. Holland. Acoustic and in-situ techniques for measuring the spatial variability of seabed geoacoustic parameters in littoral environments; J.C. Osler, et al. Measurements of bottom variability during SWAT New Jersey Shelf experiment; A. Turgut, et al. Mapping seabed variability using combined echosounder and XBPs for sonar performance prediction; K.M. Kelly, G.J. Heald. Variability of shear wave speed and attenuation in surficial marine sediments; M.D. Richardson. In-situ determination of the variability of seafloor acoustic properties: An example from the ONR Geoclutter area; L.A. Mayer, et al. Calculation of in situ acousticwave properties in marine sediments; B.J. Kraft, et al. Sub-bottom variability characterization using surface acoustic waves; M.E. Zakharia. The influence of noise and coherence fluctuations on a new geo-acoustic inversion technique; C.H. Harrison. Estimating shallow water bottom geo-acoustic parameters using ambient noise; D. Tang. Effect of environmental variability on model-based signal processing: Review of experimental results in the Mediterranean; J.-P. Hermand. Rapid geoacoustic characterization for limiting environmental uncertainty for sonar system performance prediction; K.D. Heaney, H. Cox. Environmental uncertainty in acoustic inversion; S.E. Dosso, M.J. Wilmut. Measuring the azimuthal variability of acoustic backscatter from littoral seabeds; P.C. Hines, et al. Backscatter from elastic ocean bottoms: Using the small slope model to assess acoustical variability and uncertainty; R.F. Gragg, et al. Spatial and temporal variability in bottom roughness: Implications to high frequency subcritical penetration and backscatter; K.L. Williams, et al. Variability of bottom backscattering strength in the 10-500 kHz band at shallow grazing angles; N.P. Chotiros. Predicting scattered envelope statistics of patchy seafloors; A.P. Lyons, et al. The effect of seabed backscattering variability on the probability of detection and on the performance of seabed classification algorithms; E. Pouliquen, et al. Section 3: Acoustic fluctuations: Measurements. Effects of environmental variability on acoustic propagation loss in shallow water; T. Akal. Broadband acoustic signal variability in two 'typical' shallow-water regions; P.L. Nielsen, et al. Variability, coherence and predictability of shallow water acoustic propagation in the Straits of Florida; H.A. DeFerrari, et al. Ambient no