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Center for Coastal and Ocean Mapping

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Perspectives On Ocean Mapping, Chiaki Okada, Dulap Ratnayake, Elaina O'Brien, Ellas Adediran, Nicki Andreasen, Sally Jarmusz, Sara Cardigos Jan 2022

Perspectives On Ocean Mapping, Chiaki Okada, Dulap Ratnayake, Elaina O'Brien, Ellas Adediran, Nicki Andreasen, Sally Jarmusz, Sara Cardigos

Center for Coastal and Ocean Mapping

No abstract provided.


New Hampshire And Vicinity Continental Shelf: Sand And Gravel Resources, Larry G. Ward, Zachary S. Mcavoy, Maxlimer Coromoto Vallee-Anziani Jan 2021

New Hampshire And Vicinity Continental Shelf: Sand And Gravel Resources, Larry G. Ward, Zachary S. Mcavoy, Maxlimer Coromoto Vallee-Anziani

Center for Coastal and Ocean Mapping

The continental shelf off New Hampshire (NH) has extensive marine-modified glacial deposits and associated shoals. These features are potential targets for sand and gravel resources for beach nourishment and other efforts to build coastal resiliency. The distribution of sand and gravel deposits was evaluated based on the synthesis of relatively recent high-resolution bathymetry, new surficial sediment and geoform maps, and an extensive data archive that includes over ~1280 km of seismic profiles, ~750 grain size analyses, and 23 vibracores. This work heavily utilizes the results of previous research on mineral resources on the NH shelf by Birch (1984) …


Surficial Geology Of The Continental Shelf Off New Hampshire: Morphologic Features And Surficial Sediment, Larry G. Ward, Zachary S. Mcavoy, Maxlimer Coromoto Vallee-Anziani, Rachel C. Morrison Jan 2021

Surficial Geology Of The Continental Shelf Off New Hampshire: Morphologic Features And Surficial Sediment, Larry G. Ward, Zachary S. Mcavoy, Maxlimer Coromoto Vallee-Anziani, Rachel C. Morrison

Center for Coastal and Ocean Mapping

The continental shelf off New Hampshire (NH) in the Western Gulf of Maine (WGOM) is extremely complex and includes extensive bedrock outcrops, marine-modified glacial deposits, marine-formed shoals, seafloor plains, and associated features that are composed of a range of sediment types from mud to gravel. Furthermore, the physiography and composition of the seafloor frequently changes dramatically over relatively short distances (tens of meters). The complexity of the WGOM seafloor results from the interplay of glaciations, sea-level fluctuations, and marine processes (waves and currents). High-resolution multibeam echosounder (MBES) bathymetry and backscatter surveys, along with ground truth consisting of archived seismic reflection …


Seasonal Changes In Sediment Grain Size Of New Hampshire Atlantic Beaches, Larry G. Ward, Nathan W. Corcoran, Zachary S. Mcavoy, Rachel C. Morrison Jan 2021

Seasonal Changes In Sediment Grain Size Of New Hampshire Atlantic Beaches, Larry G. Ward, Nathan W. Corcoran, Zachary S. Mcavoy, Rachel C. Morrison

Center for Coastal and Ocean Mapping

The beaches along the New Hampshire Atlantic coast are essential to the local and regional economy and are one of the major attractions of the seacoast. Beyond their economic importance, the beaches also have great aesthetic and ecological value that are vital to the character and history of New Hampshire. Unfortunately, climate change and an acceleration in sea-level rise, coupled with a major reduction in sediment supply and extensive development (including engineering structures along the coast), has led to loss of elevation and narrowing of many of the beaches. The forecast is that these trends will continue and likely become …


Erosion And Accretion Trends Of New Hampshire Beaches From December 2016 To March 2020: Results Of The Volunteer Beach Profile Monitoring Program, Larry G. Ward, Rachel C. Morrison, Alyson L. Eberhardt, Wellsley J. Costello, Zachary S. Mcavoy, Caitlin P. Mandeville Jan 2021

Erosion And Accretion Trends Of New Hampshire Beaches From December 2016 To March 2020: Results Of The Volunteer Beach Profile Monitoring Program, Larry G. Ward, Rachel C. Morrison, Alyson L. Eberhardt, Wellsley J. Costello, Zachary S. Mcavoy, Caitlin P. Mandeville

Center for Coastal and Ocean Mapping

New Hampshire Atlantic beaches were monitored from December 2016 to March 2020 to determine seasonal changes in morphology and elevation, assess the response of the beaches to storms with respect to erosion and subsequent recovery, and develop a baseline to determine long-term trends in beach size, elevation, and position. A unique aspect of this study was the involvement of community volunteers working together with the University of New Hampshire (UNH) Center for Coastal and Ocean Mapping, UNH Cooperative Extension, New Hampshire Sea Grant, and the New Hampshire Geological Survey. The monitoring network consisted of thirteen stations located at six of …


New Hampshire Atlantic Beaches: 2017 Field Campaign Database - Field And Sample Photographs And Sediment Data, Larry Ward, Nathan W. Corcoran, Zachary S. Mcavoy, Rachel C. Morrison Jan 2021

New Hampshire Atlantic Beaches: 2017 Field Campaign Database - Field And Sample Photographs And Sediment Data, Larry Ward, Nathan W. Corcoran, Zachary S. Mcavoy, Rachel C. Morrison

Center for Coastal and Ocean Mapping

Sediment data, sediment photographs, and field photographs from a major field campaign conducted on the New Hampshire Atlantic beaches in 2017 are presented here. Research was carried out with the purpose of better understanding how sediment grain size of NH beaches varies under accretional and erosional conditions. Seven major beaches along the NH coast (Wallis Sands, Foss Beach, Jenness Beach, North Hampton Beach, North Beach, Hampton Beach, and Seabrook Beach) representing the range of morphologic and sedimentologic types found on the NH coast were sampled along multiple transects and multiple locations on each transect. This work provides baseline data to …


Northeast Bathymetry And Backscatter Compilation: Western Gulf Of Maine, Southern New England, And Long Island Sound, Larry G. Ward, Paul Johnson, Michael Bogonko, Zachary S. Mcavoy, Rachel C. Morrison Jan 2021

Northeast Bathymetry And Backscatter Compilation: Western Gulf Of Maine, Southern New England, And Long Island Sound, Larry G. Ward, Paul Johnson, Michael Bogonko, Zachary S. Mcavoy, Rachel C. Morrison

Center for Coastal and Ocean Mapping

High-resolution bathymetry is critical for mapping the surficial geology of the seafloor, identifying critical habitats, and assessing marine mineral resources such as sand and gravel. In 2016, a high-resolution bathymetry map was developed for the western Gulf of Maine (WGOM) utilizing all available multibeam echosounder (MBES) surveys, as well as several older extant surveys (Western Gulf of Maine Bathymetry and Backscatter Synthesis, Ward et al., 2016). As part of that effort, a backscatter mosaic also was developed for a subset of the MBES surveys. The backscatter synthesis did not include all of the MBES surveys due to low quality of …


Analysis Of Vibracores From The New Hampshire Continental Shelf From 1984 And 1988, Larry G. Ward, Rachel C. Morrison, Zachary S. Mcavoy, Maxlimer Coromoto Vallee-Anziani Jan 2021

Analysis Of Vibracores From The New Hampshire Continental Shelf From 1984 And 1988, Larry G. Ward, Rachel C. Morrison, Zachary S. Mcavoy, Maxlimer Coromoto Vallee-Anziani

Center for Coastal and Ocean Mapping

During this study, the twenty-three vibracores taken in 1984 and 1988 were reexamined, original descriptions verified and significantly expanded, and the cores sampled to provide complete grain size data (i.e. the original sediment grain size analyses were limited). The vibracores were grouped by location with respect to major physiographic features (geoforms) or surficial sediment type including Offshore Marine-Modified Glacial Features (Drumlins and Lodgement Till Deposits), Northern Sand Body, Isles of Shoals, Nearshore Marine-Modified Glacial Features (Eskers and Drumlins), Nearshore Sheet Sand, and Offshore Seafloor Plain.

The Northern Sand Body (NSB), located near the Isles of Shoals ~10 km from shore, …


How To Recognize Crescentic Bedforms Formed By Supercritical Turbidity Currents In The Geologic Record: Insights From Active Submarine Channels, Sophie Hage, Matthieu J.B. Cartigny, Michael A. Clare, Esther J. Sumner, Daniela Vendettuoli, John E. Hughes Clarke, Stephen M. Hubbard, Peter J. Talling, D. Gwyn Lintern, Cooper D. Stacey, Rebecca G. Englert, Mark E. Vardy, James E. Hunt, Miwa Yokokawa, Daniel R. Parsons, Jamie L. Hizzett, Maria Azpiroz-Zabala, Age J. Vellinga Apr 2018

How To Recognize Crescentic Bedforms Formed By Supercritical Turbidity Currents In The Geologic Record: Insights From Active Submarine Channels, Sophie Hage, Matthieu J.B. Cartigny, Michael A. Clare, Esther J. Sumner, Daniela Vendettuoli, John E. Hughes Clarke, Stephen M. Hubbard, Peter J. Talling, D. Gwyn Lintern, Cooper D. Stacey, Rebecca G. Englert, Mark E. Vardy, James E. Hunt, Miwa Yokokawa, Daniel R. Parsons, Jamie L. Hizzett, Maria Azpiroz-Zabala, Age J. Vellinga

Center for Coastal and Ocean Mapping

Submarine channels have been important throughout geologic time for feeding globally significant volumes of sediment from land to the deep sea. Modern observations show that submarine channels can be sculpted by supercritical turbidity currents (seafloor sediment flows) that can generate upstream-migrating bedforms with a crescentic planform. In order to accurately interpret supercritical flows and depositional environments in the geologic record, it is important to be able to recognize the depositional signature of crescentic bedforms. Field geologists commonly link scour fills containing massive sands to crescentic bedforms, whereas models of turbidity currents produce deposits dominated by back-stepping beds. Here we reconcile …


The Impact Of Acoustic Imaging Geometry On The Fidelity Of Seabed Bathymetric Models, John E. Hughes Clarke Mar 2018

The Impact Of Acoustic Imaging Geometry On The Fidelity Of Seabed Bathymetric Models, John E. Hughes Clarke

Center for Coastal and Ocean Mapping

Attributes derived from digital bathymetric models (DBM) are a powerful means of analyzing seabed characteristics. Those models however are inherently constrained by the method of seabed sampling. Most bathymetric models are derived by collating a number of discrete corridors of multibeam sonar data. Within each corridor the data are collected over a wide range of distances, azimuths and elevation angles and thus the quality varies significantly. That variability therefore becomes imprinted into the DBM. Subsequent users of the DBM, unfamiliar with the original acquisition geometry, may potentially misinterpret such variability as attributes of the seabed. This paper examines the impact …


Cruise Report For Cruise Kilo Moana Km1811 In The U.S. Gulf Of Alaska Continental Margin, Joyce Miller, Andrew A. Armstrong, James V. Gardner, Paul Johnson Jan 2018

Cruise Report For Cruise Kilo Moana Km1811 In The U.S. Gulf Of Alaska Continental Margin, Joyce Miller, Andrew A. Armstrong, James V. Gardner, Paul Johnson

Center for Coastal and Ocean Mapping

Cruise report of RV Kilo Moana cruise 1811 on the U.S. margin in the Gulf of Alaska, north Pacific Ocean. The National Oceanic and Atmospheric Administration (NOAA), on behalf of the United States Government, has a requirement to carry out mapping surveys of specific regions on the margins in the Gulf of Alaska, north Pacific Ocean in order to determine the detailed bathymetry of the margins. The data are required to support any potential claim for extended jurisdiction by the United States under United Nations Convention on the Law of the Sea (UNCLOS) Article 76. The requirement is for the …


Which Triggers Produce The Most Erosive, Frequent, And Longest Runout Turbidity Currents On Deltas?, Jamie L. Hizzett, John E. Hughes Clarke, Esther J. Sumner, Peter J. Talling, Michael A. Clare Dec 2017

Which Triggers Produce The Most Erosive, Frequent, And Longest Runout Turbidity Currents On Deltas?, Jamie L. Hizzett, John E. Hughes Clarke, Esther J. Sumner, Peter J. Talling, Michael A. Clare

Center for Coastal and Ocean Mapping

Subaerial rivers and turbidity currents are the two most voluminous sediment transport processes on our planet, and it is important to understand how they are linked offshore from river mouths. Previously, it was thought that slope failures or direct plunging of river floodwater (hyperpycnal flow) dominated the triggering of turbidity currents on delta fronts. Here we reanalyze the most detailed time‐lapse monitoring yet of a submerged delta; comprising 93 surveys of the Squamish Delta in British Columbia, Canada. We show that most turbidity currents are triggered by settling of sediment from dilute surface river plumes, rather than landslides or hyperpycnal …


Preconditioning And Triggering Of Offshore Slope Failures And Turbidity Currents Revealed By Most Detailed Monitoring Yet At A Fjord-Head Delta, Michael A. Clare, John E. Hughes Clarke, Peter J. Talling, Matthieu J.B. Cartigny, D. G. Pratomo Sep 2016

Preconditioning And Triggering Of Offshore Slope Failures And Turbidity Currents Revealed By Most Detailed Monitoring Yet At A Fjord-Head Delta, Michael A. Clare, John E. Hughes Clarke, Peter J. Talling, Matthieu J.B. Cartigny, D. G. Pratomo

Center for Coastal and Ocean Mapping

Rivers and turbidity currents are the two most important sediment transport processes by volume on Earth. Various hypotheses have been proposed for triggering of turbidity currents offshore from river mouths, including direct plunging of river discharge, delta mouth bar flushing or slope failure caused by low tides and gas expansion, earthquakes and rapid sedimentation. During 2011, 106 turbidity currents were monitored at Squamish Delta, British Columbia. This enables statistical analysis of timing, frequency and triggers. The largest peaks in river discharge did not create hyperpycnal flows. Instead, delayed delta-lip failures occurred 8–11 h after flood peaks, due to cumulative delta …


First Wide-Angle View Of Channelized Turbidity Currents Links Migrating Cyclic Steps To Flow Characteristics, John E. Hughes Clarke Jun 2016

First Wide-Angle View Of Channelized Turbidity Currents Links Migrating Cyclic Steps To Flow Characteristics, John E. Hughes Clarke

Center for Coastal and Ocean Mapping

Field observations of turbidity currents remain scarce, and thus there is continued debate about their internal structure and how they modify underlying bedforms. Here, I present the results of a new imaging method that examines multiple surge-like turbidity currents within a delta front channel, as they pass over crescent-shaped bedforms. Seven discrete flows over a 2-h period vary in speed from 0.5 to 3.0 ms−1. Only flows that exhibit a distinct acoustically attenuating layer at the base, appear to cause bedform migration. That layer thickens abruptly downstream of the bottom of the lee slope of the bedform, and the upper …


New Hampshire Beaches: Sediment Characterization, Larry G. Ward, Kaitlyn A. Mcpherran, Zachary S. Mcavoy, Maxlimer Coromoto Vallee-Anziani Jan 2016

New Hampshire Beaches: Sediment Characterization, Larry G. Ward, Kaitlyn A. Mcpherran, Zachary S. Mcavoy, Maxlimer Coromoto Vallee-Anziani

Center for Coastal and Ocean Mapping

The grain size of the natural sediment composing the major New Hampshire beaches under summer equilibrium conditions was determined as a first step in assessing the optimal sediment size that would be needed for beach nourishment. In summer, 2015, seven major beaches including Wallis Sands, Foss Beach, Jenness Beach, North Hampton Beach, North Beach, Hampton Beach, and Seabrook Beach were sampled along three to five transects extending from the dunes or engineering structures (e.g., seawalls) to the low water line. In addition, the beach cross-section was profiled using a rover GPS system or the Emery method (profile rods and the …


Western Gulf Of Maine Bathymetry And Backscatter Synthesis, Larry G. Ward, Paul Johnson, Erin Nagel, Zachary S. Mcavoy, Maxlimer Coromoto Vallee-Anziani Jan 2016

Western Gulf Of Maine Bathymetry And Backscatter Synthesis, Larry G. Ward, Paul Johnson, Erin Nagel, Zachary S. Mcavoy, Maxlimer Coromoto Vallee-Anziani

Center for Coastal and Ocean Mapping

In July 2014 a Cooperative Agreement between the Bureau of Ocean Energy Management, the University of New Hampshire Center for Coastal and Ocean Mapping, and the New Hampshire Geological Survey was developed to assess the potential sand and gravel resources on the New Hampshire shelf and vicinity for the primary purpose of beach nourishment to enhance coastal resiliency. Of major importance to the effort was the development of high resolution bathymetric maps of the region to provide an understanding of the seafloor and to be used as a base for subsequent mapping products. Fortunately, over the last decade a number …


Observations Of Backscatter From Sand And Gravel Seafloors Between 170-250 Khz, Thomas C. Weber, Larry G. Ward Oct 2015

Observations Of Backscatter From Sand And Gravel Seafloors Between 170-250 Khz, Thomas C. Weber, Larry G. Ward

Center for Coastal and Ocean Mapping

Interpreting observations of frequency-dependence in backscatter from the seafloor offers many challenges, either because multiple frequencies are used for different observations that will later be merged or simply because seafloor scattering models are not well-understood above 100 kHz. Hindering the understanding of these observations is the paucity of reported, calibratedacoustic measurements above 100 kHz. This manuscript seeks to help elucidate the linkages between seafloor properties and frequency-dependent seafloor backscatter by describing observations of backscatter collected from sand, gravel, and bedrock seafloors at frequencies between 170 and 250 kHz and at a grazing angle of 45°. Overall, the frequency dependence appeared …


Initiatives In Using Crowdsourcing, Satellite Derived Bathymetry, And Other Non-Traditional Hydrographic/Bathymetric Measurements, Anthony Klemm, Shachak Pe'eri, John Nyberg Oct 2015

Initiatives In Using Crowdsourcing, Satellite Derived Bathymetry, And Other Non-Traditional Hydrographic/Bathymetric Measurements, Anthony Klemm, Shachak Pe'eri, John Nyberg

Center for Coastal and Ocean Mapping

No abstract provided.


Chart Adequacy: Workshop And Gebco Training, Limor Gur-Arieh, Yusoff Kamaruddin, Amon Kimeli, Anthony Klemm, Hirokazu Kurita, Shachak Pe'eri, Indra Budi Prasetyawan, Jae-Young Roh, Jaya Roperez, Nilupa Samarakoon, Jaqueline Sydenham, Maxlimer Vallee, Rochelle A. Wigley Oct 2015

Chart Adequacy: Workshop And Gebco Training, Limor Gur-Arieh, Yusoff Kamaruddin, Amon Kimeli, Anthony Klemm, Hirokazu Kurita, Shachak Pe'eri, Indra Budi Prasetyawan, Jae-Young Roh, Jaya Roperez, Nilupa Samarakoon, Jaqueline Sydenham, Maxlimer Vallee, Rochelle A. Wigley

Center for Coastal and Ocean Mapping

In July, 2015 the first NOAA Chart Adequacy Workshop was held in Silver Spring, Maryland, USA. Following a three-day workshop (14th to 16th July, 2015), four Nippon Foundation GEBCO students stayed at NOAA for an additional 10-day training at Office of Coast Survey’s Marine Chart Division. The key objective of the NOAA Chart Adequacy Workshop was to demonstrate techniques to evaluate the suitability of nautical chart products using chart quality information and publicly-available information. The attendees were cartographers, hydrographers and potential chart producers from hydrographic offices and government agencies around the world. The nations of the participants in the workshop …


Reconnaissance Surveying Using Satellite-Derived Bathymetry, Shachak Pe'eri, Patrick Keown, Michael Gonsalves Oct 2015

Reconnaissance Surveying Using Satellite-Derived Bathymetry, Shachak Pe'eri, Patrick Keown, Michael Gonsalves

Center for Coastal and Ocean Mapping

False Pass, AK, USA, is the eastern-most passage through the Aleutian Islands between the Bering Sea and the Pacific Ocean and provides a passage for small to mid-size vessels. The passage is considered an alternative route to Unimak Pass, AK for vessels from mainland Alaska and is estimated to be shorter by 160 to 240km. False Pass is closed every winter due to sea-ice cover that freezes the inlet system around OctoberNovember and melts only towards the spring (around March). As a result, the soft sediment of the seafloor contains mud and sand that may change the path of the …


Ambiguity Of Underwater Color Measurement And Color-Based Habitat Classification, Yuri Rzhanov, Shachak Pe'eri, A. Shashkov May 2015

Ambiguity Of Underwater Color Measurement And Color-Based Habitat Classification, Yuri Rzhanov, Shachak Pe'eri, A. Shashkov

Center for Coastal and Ocean Mapping

The paper discusses ambiguities in recording color underwater. Routinely collected RGB imagery can be used for classification and recognition utilizing the proposed probabilistic approach. The device for collection of spectral signatures, necessary for this approach is described.


Huddl: The Hydrographic Universal Data Description Language, Giuseppe Masetti, Brian R. Calder May 2015

Huddl: The Hydrographic Universal Data Description Language, Giuseppe Masetti, Brian R. Calder

Center for Coastal and Ocean Mapping

Since many of the attempts to introduce a universal hydrographic data format have failed or have been only partially successful, a different approach is proposed. Our solution is the Hydrographic Universal Data Description Language (HUDDL), a descriptive XML-based language that permits the creation of a standardized description of (past, present, and future) data formats, and allows for applications like HUDDLER, a compiler that automatically creates drivers for data access and manipulation. HUDDL also represents a powerful solution for archiving data along with their structural description, as well as for cataloguing existing format specifications and their version control. HUDDL is intended …


Developing Methodology For Efficient Eelgrass Habitat Mapping Across Lidar Systems, Victoria Price, Jennifer A. Dijkstra, Jarlath O'Neil-Dunne, Christopher Parrish, Erin Nagal, Shachak Pe'eri May 2015

Developing Methodology For Efficient Eelgrass Habitat Mapping Across Lidar Systems, Victoria Price, Jennifer A. Dijkstra, Jarlath O'Neil-Dunne, Christopher Parrish, Erin Nagal, Shachak Pe'eri

Center for Coastal and Ocean Mapping

Super Storm Sandy, the second costliest hurricane in U.S. history, made landfall on the east coast of the U.S. in October 2012. In an attempt to assess the impacts of the storm on coastal ecosystems, several U.S. mapping agencies such as the National Oceanic and Atmospheric Administration (NOAA), the U.S. Geological Survey (USGS), and the U.S. Army Corps of Engineers (USACE) commenced data collection efforts using a variety of remotely-sensed data types including aerial imagery and topobathymetric lidar. The objective of this study was to investigate the applicability of object-based image analysis techniques for benthic habitat mapping. Bathymetry and reflectance …


A Bayesian Marine Debris Detector Using Existing Hydrographic Data Products, Giuseppe Masetti, Brian R. Calder May 2015

A Bayesian Marine Debris Detector Using Existing Hydrographic Data Products, Giuseppe Masetti, Brian R. Calder

Center for Coastal and Ocean Mapping

No abstract provided.


Probabilistic Reconstruction Of Color For Species’ Classification Underwater, Yuri Rzhanov, Shachak Pe'eri, A. Shashkov May 2015

Probabilistic Reconstruction Of Color For Species’ Classification Underwater, Yuri Rzhanov, Shachak Pe'eri, A. Shashkov

Center for Coastal and Ocean Mapping

Color is probably the most informative cue for object recognition and classification in natural scenes. Difference in shades can indicate to the biologist the potential for diversity of species or stress on the habitats. However, severe color distortions may occur in underwater imagery due to wavelength-dependent attenuation of light. Affordable tri-chromatic sensors are used to record the ambient light condition and color correct the imagery, but results show that this approach works reliably only under highly controllable conditions. This paper proposes an approach that combines hyperspectral data collected for the object of interest, hardware properties of the imaging sensor, and …


Binary Adaptive Semi-Global Matching Based On Image Edges, Han Hu, Yuri Rzhanov, Philip J. Hatcher, R. D. Bergeron Apr 2015

Binary Adaptive Semi-Global Matching Based On Image Edges, Han Hu, Yuri Rzhanov, Philip J. Hatcher, R. D. Bergeron

Center for Coastal and Ocean Mapping

Image-based modeling and rendering is currently one of the most challenging topics in Computer Vision and Photogrammetry. The key issue here is building a set of dense correspondence points between two images, namely dense matching or stereo matching. Among all dense matching algorithms, Semi-Global Matching (SGM) is arguably one of the most promising algorithms for real-time stereo vision. Compared with global matching algorithms, SGM aggregates matching cost from several (eight or sixteen) directions rather than only the epipolar line using Dynamic Programming (DP). Thus, SGM eliminates the classical “streaking problem” and greatly improves its accuracy and efficiency. In this paper, …


Using Multibeam Echosounders For Hydrographic Surveying In The Water Column: Estimating Wreck Least Depths, Katrina Wyllie, Thomas C. Weber, Andy Armstrong Mar 2015

Using Multibeam Echosounders For Hydrographic Surveying In The Water Column: Estimating Wreck Least Depths, Katrina Wyllie, Thomas C. Weber, Andy Armstrong

Center for Coastal and Ocean Mapping

Wreck superstructure can extend into the water column and pose a danger to navigation if the least depth is not accurately portrayed to mariners. NOAA has several methods available to acquire a wreck least depth: lead line, wire drag, diver investigation, side scan shadow length, single beam bathymetry, and multibeam bathymetry. Previous studies have demonstrated that the bottom detection algorithm can fail to locate a wreck mast that is evident in the water column data. Modern multibeam sonars can record water column data in addition to bottom detections. NOAA’s current Hydrographic Specifications do not require water column collection; the best …


Use Of High Resolution Bathymetry And Backscatter For Mapping Depositional Environments On The New Hampshire Continental Shelf, Larry G. Ward, Zachary S. Mcavoy, Paul D. Johnson, Samuel F. Greenaway Mar 2015

Use Of High Resolution Bathymetry And Backscatter For Mapping Depositional Environments On The New Hampshire Continental Shelf, Larry G. Ward, Zachary S. Mcavoy, Paul D. Johnson, Samuel F. Greenaway

Center for Coastal and Ocean Mapping

The New Hampshire continental shelf is extremely heterogeneous and includes extensive bedrock outcrops, sand and gravel deposits and muddy basins. Many of the depositional features are glacial in origin and have been significantly modified by marine processes as sea level fluctuated since the end of the last major glaciation. Recent high resolution multibeam echosounder (MBES) bathymetric and backscatter surveys by the National Ocean Survey and University of New Hampshire Center for Coastal and Ocean Mapping/Joint Hydrographic Center has revealed features of the seafloor in exceptional detail that had not been previously described. Synthesis of the MBES bathymetry and backscatter, coupled …


Split-Beam Echosounder Observations Of Natural Methane Seep Variability In The Northern Gulf Of Mexico, Kevin W. Jerram, Thomas C. Weber, Jonathan Beaudoin Mar 2015

Split-Beam Echosounder Observations Of Natural Methane Seep Variability In The Northern Gulf Of Mexico, Kevin W. Jerram, Thomas C. Weber, Jonathan Beaudoin

Center for Coastal and Ocean Mapping

A method for positioning and characterizing plumes of bubbles from marine gas seeps using an 18 kHz scientific split-beam echo sounder (SBES) was developed and applied to acoustic observations of plumes of presumed methane gas bubbles originating at approximately 1400 m depth in the northern Gulf of Mexico. A total of 161 plume observations from 27 repeat surveys were grouped by proximity into 35 clusters of gas vent positions on the seafloor. Profiles of acoustic target strength per vertical meter of plume height were calculated with compensation for both the SBES beam pattern and the geometry of plume ensonification. These …


Integrating Industrial Laser Scanners For Small Vessel Operations, Vitad Pradith, Shachak Pe'eri, Jack Riley, Bryan Murray, David Maddock, David Oroshnik Mar 2015

Integrating Industrial Laser Scanners For Small Vessel Operations, Vitad Pradith, Shachak Pe'eri, Jack Riley, Bryan Murray, David Maddock, David Oroshnik

Center for Coastal and Ocean Mapping

The NOAA Navigation Response Teams (NRTs) perform hydrographic surveys to support nautical charting updates for 175 ports of the United States Marine Transportation System.
These include the identification of bathymetric and anthropogenic features that may pose a danger to navigation. In addition, NRTs respond to emergencies, speed the resumption of shipping after storm events, and protect life and property from underwater dangers. The spectrum of dangers occurs from natural features, such as rocks to anthropogenic objects such as piers.

Previous work conducted by the NOAA Office of Coast Survey have shown that survey-grade laser scanners can be used to remotely …