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Oceanography and Atmospheric Sciences and Meteorology

University of New Hampshire

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Articles 61 - 90 of 575

Full-Text Articles in Physical Sciences and Mathematics

The Preservation Of Atmospheric Nitrate In Snow At Summit, Greenland, Dorothy L. Fibiger, Meredith G. Hastings, Jack E. Dibb, L Gregory Huey Jul 2013

The Preservation Of Atmospheric Nitrate In Snow At Summit, Greenland, Dorothy L. Fibiger, Meredith G. Hastings, Jack E. Dibb, L Gregory Huey

Earth Sciences

There is great interest in using nitrate NO3 isotopic composition in ice cores to track the history of precursor nitrogen oxides (NOx = NO + NO2) in the atmosphere. Nitrate NO3 however can be lost from the snow by surface processes, such as photolysis back to NOx upon exposure to sunlight, making it difficult to interpret records of NO3 as a tracer of atmospheric NOx loading. In a campaign consisting of two field seasons (May–June) at Summit, Greenland, high temporal frequency surface snow samples were collected and analyzed for the oxygen isotopic composition of NO3. The strong, linear relationship observed …

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Characterization Of Optical Communication In A Leader-Follower Unmanned Underwater Vehicle Formation, Firat Eren, Shachak Pe'eri, May-Win Thein Jun 2013

Characterization Of Optical Communication In A Leader-Follower Unmanned Underwater Vehicle Formation, Firat Eren, Shachak Pe'eri, May-Win Thein

Center for Coastal and Ocean Mapping

As part of the research to development an optical communication design of a leader-follower formation between unmanned underwater vehicles (UUVs), this paper presents light field characterization and design configuration of the hardware required to allow the use of distance detection between UUVs. The study specifically is targeting communication between remotely operated vehicles (ROVs). As an initial step in this study, the light field produced from a light source mounted on the leader UUV was empirically characterized and modeled. Based on the light field measurements, a photo-detector array for the follower UUV was designed. Evaluation of the communication algorithms to monitor …

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Optimizing Resolution And Uncertainty In Bathymetric Sonar Systems, Val E. Schmidt, Thomas C. Weber, Xavier Lurton Jun 2013

Optimizing Resolution And Uncertainty In Bathymetric Sonar Systems, Val E. Schmidt, Thomas C. Weber, Xavier Lurton

Center for Coastal and Ocean Mapping

Bathymetric sonar systems (whether multibeam or phase-differencing sidescan) contain an inherent trade-off between resolution and uncertainty. Systems are traditionally designed with a fixed spatial resolution, and the parameter settings are optimized to minimize the uncertainty in the soundings within that constraint. By fixing the spatial resolution of the system, current generation sonars operate sub-optimally when the SNR is high, producing soundings with lower resolution than is supportable by the data, and inefficiently when the SNR is low, producing high-uncertainty soundings of little value. Here we propose fixing the sounding measurement uncertainty instead, and optimizing the resolution of the system within …

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Near Resonance Acoustic Scattering From Organized Schools Of Juvenile Atlantic Bluefin Tuna (Thunnus Thynnus), Thomas C. Weber, Molly Lutcavage, Madeline L. Schroth-Miller Jun 2013

Near Resonance Acoustic Scattering From Organized Schools Of Juvenile Atlantic Bluefin Tuna (Thunnus Thynnus), Thomas C. Weber, Molly Lutcavage, Madeline L. Schroth-Miller

Center for Coastal and Ocean Mapping

Schools of Atlantic bluefin tuna (Thunnus thynnus) can exhibit highly organized spatial structure within the school. This structure was quantified for dome shaped schools using both aerial imagery collected from a commercial spotter plane and 400 kHz multibeam echo sounder data collected on a fishing vessel in 2009 in Cape Cod Bay, MA. Observations from one school, containing an estimated 263 fish within an approximately ellipsoidal volume of 1900 m3, were used to seed an acoustic model that estimated the school target strength at frequencies between 10 and 2000 Hz. The fish's swimbladder resonance was estimated to occur at approximately …

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Acoustic And Optical Observations Of Methane Gas Seeps In The Gulf Of Mexico, Thomas C. Weber, Kevin W. Jerram, Yuri Rzhanov, Larry A. Mayer, Dave Lovalvo Jun 2013

Acoustic And Optical Observations Of Methane Gas Seeps In The Gulf Of Mexico, Thomas C. Weber, Kevin W. Jerram, Yuri Rzhanov, Larry A. Mayer, Dave Lovalvo

Center for Coastal and Ocean Mapping

In 2011 and 2012, measurements of acoustic backscatter from natural methane seeps were made in the northern Gulf of Mexico in water depths between 1000-2000 m. The measurementswere made using a calibrated 18 kHz echo sounder with an 11 degree beamwidth in order to estimate the depth-dependent target strength (TS). The TS data indicate a wide variation in the rate of gas seepage from the seafloor. Several of these seeps were revisited with a remotely operated vehicle in order to optically assess the bubble size distribution and to estimate the rate at which gas bubbles were exiting the seafloor. The …

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On The Export Of Reactive Nitrogen From Asia: NoX Partitioning And Effects On Ozone, T H. Bertram, Paul J. Wooldridge, Jack E. Dibb, Robert C. Cohen, A E. Perring May 2013

On The Export Of Reactive Nitrogen From Asia: NoX Partitioning And Effects On Ozone, T H. Bertram, Paul J. Wooldridge, Jack E. Dibb, Robert C. Cohen, A E. Perring

Earth Sciences

The partitioning of reactive nitrogen (NOy was measured over the remote North Pacific during spring 2006. Aircraft observations of NO, NO2, total peroxy nitrates (ΣPNs), total alkyl and multi-functional nitrates (ΣANs) and nitric acid (HNO3, made between 25° and 55° N, confirm a controlling role for peroxyacyl nitrates in NOx production in aged Asian outflow. ΣPNs account for more than 60% of NOy above 5 km, while thermal dissociation limits their contribution to less than 10% in the lower troposphere. Using simultaneous observations of NOx, ΣPNs, ΣANs, HNO3 and average …

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Satellite-Derived Bathymetry A Reconnaissance Tool For Hydrography, Shachak Pe'eri, Chukwuma Azuike, Christopher Parrish Apr 2013

Satellite-Derived Bathymetry A Reconnaissance Tool For Hydrography, Shachak Pe'eri, Chukwuma Azuike, Christopher Parrish

Center for Coastal and Ocean Mapping

In some developing countries, the information available to plan and prioritise hydrographic surveys is typically based on visual inspection of existing nautical charts. However, due to the age of many existing charts and lack of availability of the original source data from which they were compiled (e.g., smooth sheets) this type of analysis is often quite limited. A study was conducted to evaluate the use of a satellite-derived bathymetry (SDB) procedure to map shallow-water bathymetry in a GIS environment, and to identify areas that require a new hydrographic survey. Publically available, multispectral satellite imagery and published algorithms are used to …

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R/V Falkor Multibeam Echosounder System Review, Jonathan Beaudoin, Paul D. Johnson, Ashton F. Flinders Apr 2013

R/V Falkor Multibeam Echosounder System Review, Jonathan Beaudoin, Paul D. Johnson, Ashton F. Flinders

Center for Coastal and Ocean Mapping

No abstract provided.

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Underwater Radiated Noise Levels Of A Research Icebreaker In The Central Arctic Ocean, Ethan H. Roth, Val E. Schmidt, John A. Hildebrand, Sean M. Wiggins Apr 2013

Underwater Radiated Noise Levels Of A Research Icebreaker In The Central Arctic Ocean, Ethan H. Roth, Val E. Schmidt, John A. Hildebrand, Sean M. Wiggins

Center for Coastal and Ocean Mapping

U.S. Coast Guard Cutter Healy's underwater radiated noise signature was characterized in the central Arctic Ocean during different types of ice-breaking operations. Propulsion modes included transit in variable ice cover, breaking heavy ice with backing-and-ramming maneuvers, and dynamic positioning with the bow thruster in operation. Compared to open-water transit, Healy's noise signature increased approximately 10 dB between 20 Hz and 2 kHz when breaking ice. The highest noise levels resulted while the ship was engaged in backing-and-ramming maneuvers, owing to cavitation when operating the propellers astern or in opposing directions. In frequency bands centered near 10, 50, and 100 Hz, …

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Parallel And Distributed Performance Of A Depth Estimation Algorithm, Brian R. Calder Apr 2013

Parallel And Distributed Performance Of A Depth Estimation Algorithm, Brian R. Calder

Center for Coastal and Ocean Mapping

Expansion of dataset sizes and increasing complexity of processing algorithms have led to consideration of parallel and distributed implementations. The rationale for distributing the computational load may be to thin-provision computational resources, to accelerate data processing rate, or to efficiently reuse already available but otherwise idle computational resources. Whatever the rationale, an efficient solution of this type brings with it questions of data distribution, job partitioning, reliability, and robustness. This paper addresses the first two of these questions in the context of a local cluster-computing environment. Using the CHRT depth estimator, it considers active and passive data distribution and their …

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Experimental And Natural Warming Elevates Mercury Concentrations In Estuarine Fish, Jennifer A. Dijkstra, Kate L. Buckman, Darren Ward, David W. Evans, Michele Dionne, Celia Chen Mar 2013

Experimental And Natural Warming Elevates Mercury Concentrations In Estuarine Fish, Jennifer A. Dijkstra, Kate L. Buckman, Darren Ward, David W. Evans, Michele Dionne, Celia Chen

Center for Coastal and Ocean Mapping

Marine food webs are the most important link between the global contaminant, methylmercury (MeHg), and human exposure through consumption of seafood. Warming temperatures may increase human exposure to MeHg, a potent neurotoxin, by increasing MeHg production as well as bioaccumulation and trophic transfer through marine food webs. Studies of the effects of temperature on MeHg bioaccumulation are rare and no study has specifically related temperature to MeHg fate by linking laboratory experiments with natural field manipulations in coastal ecosystems. We performed laboratory and field experiments on MeHg accumulation under varying temperature regimes using the killifish, Fundulus heteroclitus. Temperature treatments were …

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Satellite-Derived Bathymetry Of The Achziv Coastal Area, Northern Israel, Shachak Pe'eri, Gideon Tibor, Brian Madore, Tomer Ketter Mar 2013

Satellite-Derived Bathymetry Of The Achziv Coastal Area, Northern Israel, Shachak Pe'eri, Gideon Tibor, Brian Madore, Tomer Ketter

Center for Coastal and Ocean Mapping

No abstract provided.

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Exploration Of Eratosthenes Seamount – A Continental Fragment Being Forced Down An Oceanic Trench, Garrett Mitchell, Larry A. Mayer, Katherine L.C. Bell, Nicole A. Raineault, Chris Roman, Robert D. Ballard, Kelsey Cornwell, Al Hine, Eugene Shinn, Iordanis Dimitriadis, Onac Bogdan Mar 2013

Exploration Of Eratosthenes Seamount – A Continental Fragment Being Forced Down An Oceanic Trench, Garrett Mitchell, Larry A. Mayer, Katherine L.C. Bell, Nicole A. Raineault, Chris Roman, Robert D. Ballard, Kelsey Cornwell, Al Hine, Eugene Shinn, Iordanis Dimitriadis, Onac Bogdan

Center for Coastal and Ocean Mapping

No abstract provided.

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Future Directions In Hydrography Using Satellite-Derived Bathymetry, Shachak Pe'eri, Christopher Parrish, Lee Alexander, Chukwuma Azuike, Andy Armstrong, Maryellen Sault Mar 2013

Future Directions In Hydrography Using Satellite-Derived Bathymetry, Shachak Pe'eri, Christopher Parrish, Lee Alexander, Chukwuma Azuike, Andy Armstrong, Maryellen Sault

Center for Coastal and Ocean Mapping

Satellite remote sensing provides useful reconnaissance tool for mapping near-shore bathymetry, characterizing a coastal area and monitoring any seafloor changes that may have occurred since the last hydrographic survey of the area. At the 2012 Canada Hydro conference, a study was presented on the potential use of Landsat satellite imagery to map shallow-water bathymetry in a GIS environment over three study sites. Since then, several collaborations between the current study group and various hydrographic organizations were established with the goal of implementing optically-derived bathymetry as part of their data acquiring procedure. Bathymetry over additional study sites around the world was …

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Developing An Acceptance Test For Non-Hydrographic Airborne Bathymetric Lidar Data Application To Noaa Charts In Shallow Waters, Gretchen Imahori, Shachak Pe'eri, Christopher Parrish, Toshi Wozumi, Stephen A. White, Inseong Jeong, Christopher L. Macon Mar 2013

Developing An Acceptance Test For Non-Hydrographic Airborne Bathymetric Lidar Data Application To Noaa Charts In Shallow Waters, Gretchen Imahori, Shachak Pe'eri, Christopher Parrish, Toshi Wozumi, Stephen A. White, Inseong Jeong, Christopher L. Macon

Center for Coastal and Ocean Mapping

Hydrographic data of the National Oceanic and Atmospheric Administration are typically acquired using sonar systems, with a small percent acquired via airborne lidar bathymetry for nearshore areas. This study investigates an integrated approach to meeting NOAA’s hydrographic survey requirements for nearshore areas of NOAA charts using existing U.S. Army Corps of Engineers (USACE) National Coastal Mapping Program (NCMP) topographic-bathymetric lidar (TBL) data. Because these existing NCMP bathymetric lidar datasets were not collected to NOAA hydrographic surveying standards, it is unclear if, and under what circumstances, they might aid in meeting certain hydrographic surveying requirements. The NCMP bathymetric lidar data were …

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Oceanographic Weather Maps: Using Oceanographic Models To Improve Seabed Mapping Planning And Acquisition, Jonathan Beaudoin, John G.W. Kelley, Jason Greenlaw, Tami Beduhn, Samuel F. Greenaway Mar 2013

Oceanographic Weather Maps: Using Oceanographic Models To Improve Seabed Mapping Planning And Acquisition, Jonathan Beaudoin, John G.W. Kelley, Jason Greenlaw, Tami Beduhn, Samuel F. Greenaway

Center for Coastal and Ocean Mapping

In a world of high precision sensors, one of the few remaining challenges in multibeam echosounding is that of refraction based uncertainty. A poor understanding of oceanographic variability can lead to inadequate sampling of the water mass and the uncertainties that result from this can dominate the uncertainty budget of even state-of-the-art echosounding systems. Though dramatic improvements have been made in sensor accuracies over the past few decades, survey accuracy and efficiency is still potentially limited by a poor understanding of the “underwater weather”. Advances in the sophistication of numerical oceanographic forecast modeling, combined with ever increasing computing power, allow …

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Report On The 2010 Rapid Assessment Survey Of Marine Species At New England Floating Docks And Rocky Shores., Christopher M. Mcintyre, Adrienne L. Pappal, Jessica Bryant, James T. Carlton, Kevin Cute, Jennifer A. Dijkstra, Renee Erickson, Yvette L. Garner, Arriaan Gittenberger, Sara P. Grady, Linsey Haram, Larry G. Harris, Niels-Viggo Hobbs, Charles C. Lambert, Gretchen Lambert, Walter J. Lambert, Antonio Carlos Marques, Arthur C. Mathieson, Megan Mcculler, Miranda Mickiewicz, Judith Pederson, Rachel Rock-Blake, Jan P. Smith, Cascade Sorte, Lauren Stefaniak, Martine Wagstaff Mar 2013

Report On The 2010 Rapid Assessment Survey Of Marine Species At New England Floating Docks And Rocky Shores., Christopher M. Mcintyre, Adrienne L. Pappal, Jessica Bryant, James T. Carlton, Kevin Cute, Jennifer A. Dijkstra, Renee Erickson, Yvette L. Garner, Arriaan Gittenberger, Sara P. Grady, Linsey Haram, Larry G. Harris, Niels-Viggo Hobbs, Charles C. Lambert, Gretchen Lambert, Walter J. Lambert, Antonio Carlos Marques, Arthur C. Mathieson, Megan Mcculler, Miranda Mickiewicz, Judith Pederson, Rachel Rock-Blake, Jan P. Smith, Cascade Sorte, Lauren Stefaniak, Martine Wagstaff

Center for Coastal and Ocean Mapping

No abstract provided.

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Distribution-Free, Variable Resolution Depth Estimation With Composite Uncertainty, Brian R. Calder Mar 2013

Distribution-Free, Variable Resolution Depth Estimation With Composite Uncertainty, Brian R. Calder

Center for Coastal and Ocean Mapping

Recent algorithms for processing hydrographic data have treated the problem of achievable resolution by constructing grids of fixed resolution, a composite grid of variable resolution, recursive sub-division in a quad-tree, or by relying on a comprehensive TIN of the original points. These algorithms all impose some artificial structure on the data to allow for efficient computation, however, which this paper attempts to address. A scheme is outlined which provides a robust estimate of depth and associated uncertainty that makes as few assumptions as possible. Using a non-uniform spectral analysis, it estimates the spatial scales at which the data are consistent …

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A Single Vessel Approach To Inter-­Vessel Normalization Of Seafloor Backscatter Data, Samuel F. Greenaway, Glen Rice Mar 2013

A Single Vessel Approach To Inter-­Vessel Normalization Of Seafloor Backscatter Data, Samuel F. Greenaway, Glen Rice

Center for Coastal and Ocean Mapping

Integration!of!backscatter!data!from!multiple!unTcalibrated!echosounders remains!a!challenge.!! The!arbitrary!offsets!that!are!acceptable!within!a!single!sensor!application!become!problematic! when!integrating!multiple!sensors!into!a!common!data!set.!!Instruments!typically!have! differences!in!overall!sensitivities!and/!or!beam!patterns!that!are!large!enough!to!complicate! the!combination!of!the!individual!sensor!data!sets!into!a!coherent,!project!wide!product.! The!dualThead!Reson!7125!installation!on!the!NOAA!Ship!Ferdinand!R.!Hassler!is!useful! intermediate!step!between!a!single!instrument!installation!and!a!true!multiTvessel!application.!! When!operated!simultaneously,!the!temporal!variation!in!the!acoustic!properties!of!the! seafloor!and!the!water!column!can!be!eliminated!between!the!two!systems.!!! Using!data!acquired!during!production!hydrography,!we!solve!for!the!offsets!between!the!two! heads!for!simultaneously!logged!data.!!This!approach!is!then!broadened!to!determine!offsets! between!different!days,!and!then!different!hardware!installations!throughout!the!project.!!!We! find!that!the!normalization!offsets!vary!significantly!between!the!heads,!between!different!runs! (likely!due!to!the!Reson!normalization process),!and!different!installed!receiver!components.!! Accounting!for!these!offsets,!we!are!able!to!generate!project!wide!mosaics!and!backscatter! products.

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Water-Column Variability Assessment For Underway Profilers To Improve Efficiency And Accuracy Of Multibeam Surveys, Matt Wilson, Jonathan Beaudoin, Steve Smyth Mar 2013

Water-Column Variability Assessment For Underway Profilers To Improve Efficiency And Accuracy Of Multibeam Surveys, Matt Wilson, Jonathan Beaudoin, Steve Smyth

Center for Coastal and Ocean Mapping

With the advent of underway profilers, sampling the water-column to obtain sound speed corrections is no longer a detriment to hydrographic survey efficiency. Instead, the challenge has become deciding how many casts are necessary to maintain a desired level of multibeam sounding accuracy, while not needlessly overworking the profiler. Ray tracing uncertainty analysis can determine in hindsight whether a particular sampling interval is adequate or not. Based on this methodology, an algorithm was developed to generate recommended sampling intervals based on successively acquired sound speed profiles, allowing the MVP to run in a “cruise-control” mode where the sampling interval is …

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A Procedure For Developing An Acceptance Test For Airborne Bathymetric Lidar Data Application To Noaa Charts In Shallow Waters, Gretchen Imahori, Jeffrey Ferguson, Toshi Wozumi, Dave Scharff, Shachak Pe'eri, Christopher Parrish, Stephen A. White, Inseong Jeong, Jon Sellars, Michael Aslaksen Jan 2013

A Procedure For Developing An Acceptance Test For Airborne Bathymetric Lidar Data Application To Noaa Charts In Shallow Waters, Gretchen Imahori, Jeffrey Ferguson, Toshi Wozumi, Dave Scharff, Shachak Pe'eri, Christopher Parrish, Stephen A. White, Inseong Jeong, Jon Sellars, Michael Aslaksen

Center for Coastal and Ocean Mapping

National Oceanic and Atmospheric Administration (NOAA) hydrographic data is typically acquired using sonar systems, with a small percent acquired via airborne lidar bathymetry for near‐shore areas. This study investigated an integrated approach for meeting NOAA’s hydrographic survey requirements for near‐shore areas of NOAA charts, using the existing topographic‐bathymetric lidar data from USACE’s National Coastal Mapping Program (NCMP). Because these existing NCMP bathymetric lidar datasets were not collected to NOAA hydrographic surveying standards, it is unclear if, and under what circumstances, they might aid in meeting certain hydrographic surveying requirements. The NCMP’s bathymetric lidar data are evaluated through a comparison to …

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Spectral Characterization Of The Nigerian Shoreline Using Landsat Imagery, Olumide Fadahunsi, Shachak Pe'eri, Christopher Parrish, Andy Armstrong, Lee Alexander Jan 2013

Spectral Characterization Of The Nigerian Shoreline Using Landsat Imagery, Olumide Fadahunsi, Shachak Pe'eri, Christopher Parrish, Andy Armstrong, Lee Alexander

Center for Coastal and Ocean Mapping

The challenges of shoreline mapping include the high costs of acquiring up-to-date survey data over the coastal area. As a result, in many developing countries, the shoreline has not been consistently mapped. The variety of methods used for this mapping and the large time differences between the surveys (on the order of decades) could result in inaccuracies in shoreline data. This study presents the development of a shoreline characterization procedure for the Nigerian coastline using satellite remote sensing technology. The study goal is to produce a complete, consistent and continuous shoreline map using publicly available data processed in a GIS …

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Seabed Classification For Trawlability Determined With A Multibeam Echo Sounder On Snakehead Bank In The Gulf Of Alaska, Thomas C. Weber, Chris Rooper, John L. Butler, Darin Jones, Chris Wilson Jan 2013

Seabed Classification For Trawlability Determined With A Multibeam Echo Sounder On Snakehead Bank In The Gulf Of Alaska, Thomas C. Weber, Chris Rooper, John L. Butler, Darin Jones, Chris Wilson

Center for Coastal and Ocean Mapping

—Rockfishes (Sebastes spp.) tend to aggregate near rocky, cobble, or generally rugged areas that are difficult to survey with bottom trawls, and evidence indicates that assemblages of rockfish species may differ between areas accessible to trawling and those areas that are not. Consequently, it is important to determine grounds that are trawlable or untrawlable so that the areas where trawl survey results should be applied are accurately identified. To this end, we used multibeam echosounder data to generate metrics that describe the seafloor: backscatter strength at normal and oblique incidence angles, the variation of the angle-dependent backscatter strength within 10° …

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Ricamar2013: Rilievi Per La Caratterizzazione Dell'ambiente Marino Nel Golfo Di Pozzuoli. Rapporto Sull'attivita 13 - 31 Maggio 2013, C. Carmisciano, M. Grassi, L. Cocchi, Giuseppe Masetti, M. Filippone, E. Ricci, M. Pratellesi, Roberta Ivaldi, Giovanni Iannaccone, Giovanna Berrino, Guiseppe De Natale, Giovanni Chiodini, Sefano Caliro, Lorenzo Dialti, Matteo Guideri, F. Muccini, Paolo Stefanelli, Giovanni Orsi, Valerio Iafolla, Francesco Italiano, Fabrizia Buongiorno, Salvatore Stramondo, Christian Bignami, Marco Polcari, Malvina Silvestri Jan 2013

Ricamar2013: Rilievi Per La Caratterizzazione Dell'ambiente Marino Nel Golfo Di Pozzuoli. Rapporto Sull'attivita 13 - 31 Maggio 2013, C. Carmisciano, M. Grassi, L. Cocchi, Giuseppe Masetti, M. Filippone, E. Ricci, M. Pratellesi, Roberta Ivaldi, Giovanni Iannaccone, Giovanna Berrino, Guiseppe De Natale, Giovanni Chiodini, Sefano Caliro, Lorenzo Dialti, Matteo Guideri, F. Muccini, Paolo Stefanelli, Giovanni Orsi, Valerio Iafolla, Francesco Italiano, Fabrizia Buongiorno, Salvatore Stramondo, Christian Bignami, Marco Polcari, Malvina Silvestri

Center for Coastal and Ocean Mapping

No abstract provided.

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Combining Angular And Spatial Information From Multibeam Backscatter Data For Improved Unsupervised Acoustic Seabed Segmentation, Alexandre C. Schimel, Yuri Rzhanov, Luciano E. Fonseca, M Mayer, Dirk Immenga Jan 2013

Combining Angular And Spatial Information From Multibeam Backscatter Data For Improved Unsupervised Acoustic Seabed Segmentation, Alexandre C. Schimel, Yuri Rzhanov, Luciano E. Fonseca, M Mayer, Dirk Immenga

Center for Coastal and Ocean Mapping

No abstract provided.

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Observations Of The Vertical Structure Of Tidal Currents In Two Inlets, Thomas C. Lippmann, James D. Irish, Jonathan Hunt Jan 2013

Observations Of The Vertical Structure Of Tidal Currents In Two Inlets, Thomas C. Lippmann, James D. Irish, Jonathan Hunt

Center for Coastal and Ocean Mapping

Observations of the vertical structure of broad band tidal currents were obtained at two energetic inlets. Each experiment took place over a 4 week period, the first at Hampton Inlet in southeastern New Hampshire, USA, in the Fall of 2011, and the second at New River Inlet in southern North Carolina, USA, in the spring of 2012. The temporal variation and vertical structure of the currents were observed at each site with 600 kHz and 1200 kHz RDI Acoustic Doppler Current Profilers (ADCP) deployed on low-profile bottom tripods in 7.5 and 12.5 m water depths near the entrance to Hampton …

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Bathymetric Terrain Model Of The Atlantic Margin For Marine Geological Investigations., Brian Andrews, Jason D. Chaytor, Uri S. Ten Brink, Daniel S. Brothers, James V. Gardner Jan 2013

Bathymetric Terrain Model Of The Atlantic Margin For Marine Geological Investigations., Brian Andrews, Jason D. Chaytor, Uri S. Ten Brink, Daniel S. Brothers, James V. Gardner

Center for Coastal and Ocean Mapping

Bathymetric terrain models of seafloor morphology are an important component of marine geological investigations. Advances in acquisition and processing technologies of bathymetric data have facilitated the creation of high-resolution bathymetric surfaces that approach the resolution of similar surfaces available for onshore investigations. These bathymetric terrain models provide a detailed representation of the Earth’s subaqueous surface and, when combined with other geophysical and geological datasets, allow for interpretation of modern and ancient geological processes. The purpose of the bathymetric terrain model presented in this report is to provide a high-quality bathymetric surface of the Atlantic margin of the United States that …

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Scientific Basis For Safely Shutting In The Macondo Well After The April 20, 2010 Deepwater Horizon Blowout, Stephen H. Hickman, Paul A. Hsieh, Walter D. Mooney, Catherine B. Enomoto, Philip H. Nelson, Larry A. Mayer, Thomas C. Weber, Kathryn Moran, P. B. Flemings, Marcia Mcnutt Dec 2012

Scientific Basis For Safely Shutting In The Macondo Well After The April 20, 2010 Deepwater Horizon Blowout, Stephen H. Hickman, Paul A. Hsieh, Walter D. Mooney, Catherine B. Enomoto, Philip H. Nelson, Larry A. Mayer, Thomas C. Weber, Kathryn Moran, P. B. Flemings, Marcia Mcnutt

Center for Coastal and Ocean Mapping

As part of the government response to the Deepwater Horizon blowout, a Well Integrity Team evaluated the geologic hazards of shutting in the Macondo Well at the seafloor and determined the conditions under which it could safely be undertaken. Of particular concern was the possibility that, under the anticipated high shut-in pressures, oil could leak out of the well casing below the seafloor. Such a leak could lead to new geologic pathways for hydrocarbon release to the Gulf of Mexico. Evaluating this hazard required analyses of 2D and 3D seismic surveys, seafloor bathymetry, sediment properties, geophysical well logs, and drilling …

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Overview Of The 2007 And 2008 Campaigns Conducted As Part Of The Greenland Summit Halogen-HoX Experiment (Gshox), J L. Thomas, Jack E. Dibb, J Stutz, R Von Glasow, Steve Brooks, L Gregory Huey, Barry Lefer Nov 2012

Overview Of The 2007 And 2008 Campaigns Conducted As Part Of The Greenland Summit Halogen-HoX Experiment (Gshox), J L. Thomas, Jack E. Dibb, J Stutz, R Von Glasow, Steve Brooks, L Gregory Huey, Barry Lefer

Earth Sciences

From 10 May through 17 June 2007 and 6 June through 9 July 2008 intensive sampling campaigns at Summit, Greenland confirmed that active bromine chemistry is occurring in and above the snow pack at the highest part of the Greenland ice sheet (72°36´ N, 38°25´ W and 3.2 km above sea level). Direct measurements found BrO and soluble gas phase Br− mixing ratios in the low pptv range on many days (maxima < 10 pptv). Conversion of up to 200 pg m−3 of gaseous elemental mercury (GEM) to reactive gaseous mercury (RGM) and enhanced OH relative to HO2 plus RO2 confirm that active bromine chemistry is …

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Calibration Of Multibeam Echo Sounders: A Comparison Between Two Methodologies, Carlo Lanzoni, Thomas C. Weber Nov 2012

Calibration Of Multibeam Echo Sounders: A Comparison Between Two Methodologies, Carlo Lanzoni, Thomas C. Weber

Center for Coastal and Ocean Mapping

Multibeam echo sounders (MBES) are widely used in applications like seafloor imaging, fisheries, and habitat mapping. Calibration of acoustic backscatter is an important aspect of understanding and validating the performance of a MBES. Combined transmit/receive beampattern calibrations were performed on a 200 kHz Reson Seabat 7125 MBES in the acoustic tank of the University of New Hampshire utilizing two different methodologies. The first methodology employs fixed standard target spheres and a high accuracy/high resolution rotation mechanism. This method, similar to that proposed by Foote et al ["Protocols forcalibrating multibeam sonar", J. Acoust. Soc. Am. 117(4), 2005], is designed for a …

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