Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 13 of 13
Full-Text Articles in Entire DC Network
Remote Characterization Of Seafloor Adjacent To Shipwrecks Using Mosaicking And Analysis Of Backscatter Response, Giuseppe Masetti, Roberto Sacile, Andrea Trucco
Remote Characterization Of Seafloor Adjacent To Shipwrecks Using Mosaicking And Analysis Of Backscatter Response, Giuseppe Masetti, Roberto Sacile, Andrea Trucco
Center for Coastal and Ocean Mapping
The paper’s aim is to evaluate mosaicking and analysis of backscatter angular responses as adequate techniques to quickly characterize the seafloor adjacent to shipwrecks, extending the results of a limited number of grabs. Both techniques have been applied to the casestudy of the VLCC Haven shipwreck site, applying the approach known as Geocoder among the available methods. From these results, the development of the research activities will attempt to improve techniques and to generalize a methodological approach for the analysis of backscatter coming from an area of seafloor with the presence of one or more anthropic objects.
Acquisizione Magnetica Marina Dell'alto Strutturale Del Mt. Vercelli (Mar Tirreno Centrale) E Del Golfo Di Napoli: Descrizione Dei Rilievi E Primi Risultati, L. Cocchi, F. Muccini, C. Carmisciano, R. Vagni, Giuseppe Masetti
Acquisizione Magnetica Marina Dell'alto Strutturale Del Mt. Vercelli (Mar Tirreno Centrale) E Del Golfo Di Napoli: Descrizione Dei Rilievi E Primi Risultati, L. Cocchi, F. Muccini, C. Carmisciano, R. Vagni, Giuseppe Masetti
Center for Coastal and Ocean Mapping
Durante la Campagna Oceanografica Ver2010, effettuata nel mese di maggio 2010, sono stati acquisiti due set di dati geomagnetici marini in alta risoluzione relativi alle aree del Mt. Vercelli (Mar Tirreno Centrale) e del Golfo di Napoli. Tale attività di misura è stata resa possibile grazie alla collaborazione tecnica scientifica tra l’Unità di Progetto “Geofisica e Tecnologie Marine” dell’Istituto Nazionale di Geofisica e Vulcanologia (INGV) e l’Istituto Idrografico della Marina (IIM). La proficua collaborazione è sancita dall’accordo di cooperazione “Co.Na.Ge.M” (Coordinamento Nazionale per la Geofisica Marina). Nello specifico, i due rilievi sono stati svolti mediante l’impiego della Nave Idro-oceanografica “Aretusa”, …
High-Resolution Seafloor Mapping And An Assessment Of The Effectiveness Of The Western Gulf Of Maine Closure Area (Wgomca), Raymond E. Grizzle, Mashkoor A. Malik, Larry G. Ward
High-Resolution Seafloor Mapping And An Assessment Of The Effectiveness Of The Western Gulf Of Maine Closure Area (Wgomca), Raymond E. Grizzle, Mashkoor A. Malik, Larry G. Ward
Center for Coastal and Ocean Mapping
No abstract provided.
Automatic Construction Of Acoustic Themes For Benthic Habitat Mapping At Stanton Banks, Uk, Luciano E. Fonseca, Yuri Rzhanov, C Mcgonigle, Craig Brown
Automatic Construction Of Acoustic Themes For Benthic Habitat Mapping At Stanton Banks, Uk, Luciano E. Fonseca, Yuri Rzhanov, C Mcgonigle, Craig Brown
Center for Coastal and Ocean Mapping
In recent years, many attempts have been made to develop automatic methods for segmentation of hydroacoustic remote sensing data acquired by multibeam echosounders (MBES) in order to generate quantitative estimates of the spatial distribution of seafloor relief, bottom type and composition. The majority of the segmentation methods presented so far have been based on image processing techniques, which assume implicitly the existence of an image. This limits their ability to unambiguously discriminate seafloor properties, as the primary observation of an MBES is not backscatter imagery or mosaics, but rather backscatter angular response. Mosaics are only projections of the original observations, …
Future Impacts Of Fresh Water Resource Management: Sensitivity Of Coastal Deltas, Charles J. Vorosmarty, Jason P. Ericson, S Lawrence Dingman, Larry G. Ward
Future Impacts Of Fresh Water Resource Management: Sensitivity Of Coastal Deltas, Charles J. Vorosmarty, Jason P. Ericson, S Lawrence Dingman, Larry G. Ward
Center for Coastal and Ocean Mapping
We present an assessment of contemporary and future effective sealevel rise (ESLR) using a sample of 40 deltas distributed worldwide. For any delta, ESLR is a net rate defined by eustatic sea-level rise, natural gross rates of fluvial sediment deposition and subsidence, and accelerated subsidence due to groundwater and hydrocarbon extraction. Present-day ESLR, estimated from geospatial data and a simple model of deltaic dynamics, ranges from 0.5 to 12.5 mm year-1. Reduced accretion of fluvial sediment from upstream siltation of reservoirs and freshwater consumptive irrigation losses are primary determinants of ESLR in nearly 70% of the deltas, while for only …
A Multibeam Survey Of Mid-Seneca Lake: Bathymetry, Backscatter, And Invasive Species, Thomas C. Weber, Anthony P. Lyons
A Multibeam Survey Of Mid-Seneca Lake: Bathymetry, Backscatter, And Invasive Species, Thomas C. Weber, Anthony P. Lyons
Center for Coastal and Ocean Mapping
No abstract provided.
Seafloor Characterization Through The Application Of Avo Analysis To Multibeam Sonar Data, Luciano E. Fonseca, Larry A. Mayer, Barbara J. Kraft
Seafloor Characterization Through The Application Of Avo Analysis To Multibeam Sonar Data, Luciano E. Fonseca, Larry A. Mayer, Barbara J. Kraft
Center for Coastal and Ocean Mapping
In the seismic reflection method, it is well known that seismic amplitude varies with the offset between the seismic source and detector and that this variation is a key to the direct determination of lithology and pore fluid content of subsurface strata. Based on this fundamental property, amplitude-versus-offset (AVO) analysis has been used successfully in the oil industry for the exploration and characterization of subsurface reservoirs. Multibeam sonars acquire acoustic backscatter over a wide range of incidence angles and the variation of the backscatter with the angle of incidence is an intrinsic property of the seafloor. Building on this analogy, …
Quantitative Inter-Channel Calibration Of Shoals Signals For Consistent Bottom Segmentation And Characterization, Semme J. Dijkstra, G. Elston
Quantitative Inter-Channel Calibration Of Shoals Signals For Consistent Bottom Segmentation And Characterization, Semme J. Dijkstra, G. Elston
Center for Coastal and Ocean Mapping
No abstract provided.
Remote Sensing Of Sediment Characteristics By Optimized Echo-Envelope Matching, Daniel D. Sternlicht, Christian De Moustier
Remote Sensing Of Sediment Characteristics By Optimized Echo-Envelope Matching, Daniel D. Sternlicht, Christian De Moustier
Center for Coastal and Ocean Mapping
A sediment geoacoustic parameter estimation technique is described which compares bottom returns, measured by a calibrated monostatic sonar oriented within 15° of vertical and having a 10°–21° beamwidth, with an echo envelope model based on high-frequency (10–100 kHz) incoherent backscattertheory and sediment properties such as: mean grain size, strength, and exponent of the power law characterizing the interface roughness energy density spectrum, and volume scattering coefficient. An average echo envelope matching procedure iterates on the reflection coefficient to match the peak echo amplitude and separate coarse from fine-grain sediments, followed by a global optimization using a combination of simulated annealing …
Mapping And Characterizing Subtidal Oyster Reefs Using Acoustic Techniques, Underwater Videography And Quadrat Counts, Raymond E. Grizzle, J R. Adams, Semme J. Dijkstra, Brian Smith, R W. Ward
Mapping And Characterizing Subtidal Oyster Reefs Using Acoustic Techniques, Underwater Videography And Quadrat Counts, Raymond E. Grizzle, J R. Adams, Semme J. Dijkstra, Brian Smith, R W. Ward
Center for Coastal and Ocean Mapping
Populations of the eastern oyster Crassostrea virginica have been in long-term decline in most areas. A major hindrance to effective oyster management has been lack of a methodology for accurately and economically obtaining data on their distribution and abundance patterns. Here, we describe early results from studies aimed at development of a mapping and monitoring protocol involving acoustic techniques, underwater videography, and destructive sampling (excavated quadrats). Two subtidal reefs in Great Bay, New Hampshire, were mapped with side-scan sonar and with videography by systematically imaging multiple sampling cells in a grid covering the same areas. A single deployment was made …
Near Bottom Sediment Characterization Offshore Sw San Clemente Island, Daniel D. Sternlicht, Christian De Moustier
Near Bottom Sediment Characterization Offshore Sw San Clemente Island, Daniel D. Sternlicht, Christian De Moustier
Center for Coastal and Ocean Mapping
Normal incidence, 23.5 kHz seafloor acoustic backscatter data and bottom video were measured with the Deep Tow instrument package of the Scripps Institution of Oceanography in 100 meter water depth south of San Clemente Island, CA. The collected data were processed using an echo envelopesediment characterization method, to derive geoacoustic parameters such as particle mean grain size and the strength of the power law characterizing the roughness energy density spectrum of thesediment-water interface. Two regions, sand and silt, were selected based on available ground truth, perceived along-track sediment homogeneity, data quality and tow fish stability. Distinction between sand and fine …
Quantitative Ground-Truthing Of Habitat Characteristics Using Video Mosaic Images, Randy G. Cutter Jr., Yuri Rzhanov, Larry A. Mayer
Quantitative Ground-Truthing Of Habitat Characteristics Using Video Mosaic Images, Randy G. Cutter Jr., Yuri Rzhanov, Larry A. Mayer
Center for Coastal and Ocean Mapping
No abstract provided.
Seafloor Characterization From Spatial Variation Of Multibeam Backscatter Vs. Grazing Angle, Tianhang Hou, Lloyd C. Huff, Yuri Rzhanov, Larry A. Mayer
Seafloor Characterization From Spatial Variation Of Multibeam Backscatter Vs. Grazing Angle, Tianhang Hou, Lloyd C. Huff, Yuri Rzhanov, Larry A. Mayer
Center for Coastal and Ocean Mapping
Backscatter vs. grazing angle, which can be extracted from multibeam backscatter data, depend on characteristics of the multibeam system and the angular responses of backscatter that are characteristic of different seafloor properties, such as sediment hardness and roughness. Changes in backscatter vs. grazing angle that are contributed by the multibeam system normally remain fixed over both space and time. Therefore, they can readily be determined and removed from backscatter data. The variation of backscatter vs. grazing angle due to the properties of sediments will vary from location to location, as sediment type changes. The sediment component of variability can be …