Oceanography and Atmospheric Sciences and Meteorology Commons^™

A Modeling Experiment On The Grounding Of An Ice Shelf In The Central Arctic Ocean During Mis 6, Martin Jakobsson, M Siegert, Mark Paton

Center for Coastal and Ocean Mapping

High-resolution chirp sonar subbottom profiles from the Lomonosov Ridge in the central Arctic Ocean, acquired from the Swedish icebreaker Oden in 1996, revealed large-scale erosion of the ridge crest down to depths of 1000 m below present sea level [Jakobsson, 1999]. Subsequent acoustic mapping during the SCICEX nuclear submarine expedition in 1999 showed glacial fluting at the deepest eroded areas and subparallel ice scours from 950 m water depth to the shallowest parts of the ridge crest [Polyak et al., 2001]. The directions of the mapped glaciogenic bed-forms and the redeposition of eroded material on the Amerasian side of the …

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 …

Hypsometry, Volume And Physiography Of The Arctic Ocean And Their Paleoceanographic Implications, Martin Jakobsson, Ron Macnab, Arthur Grantz, Yngue Kristoffersen

Center for Coastal and Ocean Mapping

Recent analyses of the International Bathymetric Chart of the Arctic Ocean (IBCAO) grid model include: Hypsometry (the distribution of surface area at various depths); ocean volume distribution; and physiographic provinces [Jakobsson 2002; Jakobsson et al., in press]. The present paper summarizes the main results from these recent studies and expands on the paleoceanographic implications for the Arctic Ocean, which in this work is defined as the broad continental shelves of the Barents, Kara, Laptev, East Siberian and Chukchi Seas, the White Sea and the narrow continental shelves of the Beaufort Sea, the Arctic continental margins off the Canadian Arctic Archipelago …

Time Dependent Seafloor Acoustic Backscatter (10-100khz), Daniel D. Sternlicht, Christian De Moustier

Center for Coastal and Ocean Mapping

A time-dependent model of the acoustic intensity backscattered by the seafloor is described and compared with data from a calibrated, vertically oriented, echo-sounder operating at 33 and 93 kHz. The model incorporates the characteristics of the echo-sounder and transmitted pulse, and the water column spreading and absorption losses. Scattering from the water–sediment interface is predicted using Helmholtz–Kirchhoff theory, parametrized by the mean grain size, the coherent reflection coefficient, and the strength and exponent of a power-law roughness spectrum. The composite roughness approach of Jackson et al. [J. Acoust. Soc. Am. 79, 1410–1422 (1986)], modified for the finite duration of …

High-Frequency Volume And Boundary Acoustic Backscatter Fluctuations In Shallow Water, Timothy C. Gallaudet, Christian De Moustier

Center for Coastal and Ocean Mapping

Volume and boundary acoustic backscatter envelope fluctuations are characterized from data collected by the Toroidal Volume Search Sonar (TVSS), a 68 kHz cylindrical array capable of 360° multibeam imaging in the vertical plane perpendicular to its axis. The data are processed to form acoustic backscatter images of the seafloor, sea surface, and horizontal and vertical planes in the volume, which are used to attribute nonhomogeneous spatial distributions of zooplankton, fish, bubbles and bubble clouds, and multiple boundary interactions to the observed backscatter amplitude statistics. Three component Rayleigh mixture probability distribution functions (PDFs) provided the best fit to the empirical distribution …

Haptic-Geozui3d: Exploring The Use Of Haptics In Auv Path Planning, Rick Komerska, Colin Ware

Center for Coastal and Ocean Mapping

We have developed a desktop virtual reality system that we call Haptic-GeoZui3D, which brings together 3D user interaction and visualization to provide a compelling environment for AUV path planning. A key component in our system is the PHANTOM haptic device (SensAble Technologies, Inc.), which affords a sense of touch and force feedback – haptics – to provide cues and constraints to guide the user’s interaction. This paper describes our system, and how we use haptics to significantly augment our ability to lay out a vehicle path. We show how our system works well for quickly defining simple waypoint-towaypoint (e.g. transit) …

Haptic-Geozui3d: Exploring The Use Of Haptics In Auv Path Planning, Rick Komerska, Colin Ware, Matthew D. Plumlee, Roland J. Arsenault

Center for Coastal and Ocean Mapping

No abstract provided.

Report On The Lots Cruise To Map Foot Of The Slope And 2500-M Isobath Of Bowers Ridge And Beringian Margin, Bering Sea. Cruise Report, James V. Gardner

Center for Coastal and Ocean Mapping

Report on the LOTS cruise to map foot of the slope and 2500-m isobath of Bowers Ridge and Beringian margin, Bering Sea

July 7, to July 28, 2003

Dutch Harbor, AK to Dutch Harbor, AK

Integrating Multiple 3d Views Through Frame-Of-Reference Interaction, Matthew D. Plumlee, Colin Ware

Center for Coastal and Ocean Mapping

Frame-of-reference interaction consists of a unified set of 3D interaction techniques for exploratory navigation of large virtual spaces in nonimmersive environments. It is based on a conceptual framework that considers navigation from a cognitive perspective, as a way of facilitating changes in user attention from one reference frame to another, rather than from the mechanical perspective of moving a camera between different points of interest. All of our techniques link multiple frames of reference in some meaningful way. Some techniques link multiple windows within a zooming environment while others allow seamless changes of user focus between static objects, moving objects, …

Automatic Processing Of High-Rate, High-Density Multibeam Echosounder Data, Brian R. Calder, Larry A. Mayer

Center for Coastal and Ocean Mapping

Multibeam echosounders (MBES) are currently the best way to determine the bathymetry of large regions of the seabed with high accuracy. They are becoming the standard instrument for hydrographic surveying and are also used in geological studies, mineral exploration and scientific investigation of the earth's crustal deformations and life cycle. The significantly increased data density provided by an MBES has significant advantages in accurately delineating the morphology of the seabed, but comes with the attendant disadvantage of having to handle and process a much greater volume of data. Current data processing approaches typically involve (computer aided) human inspection of all …

Analysis Of Data Relevant To Establishing Outer Limits Of A Continental Shelf Under Law Of The Sea Article 76, Martin Jakobsson, Larry A. Mayer, Andy Armstrong

Center for Coastal and Ocean Mapping

Coastal states may extend the limits of their juridically defined continental shelf beyond 200 nautical miles from their baselines under the provisions set forth in Article 76 of the United Nations Convention on the Law of the Sea (UNCLOS). In a preparatory desktop study, the University of New Hampshire’s Center for Coastal and Ocean Mapping/Joint Hydrographic Center analysed existing U.S. bathymetric and geophysical data holdings, identified data adequacy, and survey requirements to prepare a U.S. claim beyond the Exclusive Economical Zone (EEZ). In this paper we describe the methodology for our desktop study with particular emphasis on how we assembled …

Paleomagnetic Chronology Of Arctic Ocean Sediment Cores: Reversals And Excursions -The Conundrum, Reidar Lovlie, Martin Jakobsson, Jan Backman

Center for Coastal and Ocean Mapping

Chronologies of Arctic Ocean sediment cores are mainly based on interpretation of paleomagnetic inclination records. The first paleomagnetic chronology assigned zones with negative inclinations to polarity reversals (Steuerwald et al, 1968) because geomagnetic excursions at that time were a novel observation and had only been reported from lavas. Arctic Ocean sedimentation rates were thus established to be in the mm/ka-range. A general recognition of excursions as real features of the geomagnetic field emerged more than three decades later, and presently there is still no consensus regarding the number (or name), duration and age of global synchronous excursions within the Brunhes …

The International Bathymetric Chart Of The Arctic Ocean (Ibcao): An Improved Morphological Framework For Oceanographic Investigations, Ron Macnab, Martin Jakobsson

Center for Coastal and Ocean Mapping

The IBCAO initiative set out in late 1997 to assemble and merge all available bathymetric observations from northern regions, with the intent of constructing a reliable and up-to-date portrayal of the Arctic seabed in digital and printed form. In early 2000, a provisional grid and map were placed in circulation for public review and comment. Available for free downloading from a website hosted by the U.S. National Geophysical Data Center, these products won immediate acceptance from a broad spectrum of Arctic investigators who recognized the potential worth of the new information in a variety of applications ranging from straightforward map …

Fusing Information In A 3d Chart-Of-The-Future Display, Roland J. Arsenault, Matthew D. Plumlee, Shep M. Smith Lt, Colin Ware, Rick Brennan, Larry A. Mayer

Center for Coastal and Ocean Mapping

No abstract provided.

Fusing Information In A 3d Chart-Of-The-Future Display, Roland J. Arsenault, Shep M. Smith Lt, Colin Ware, Larry A. Mayer, Matthew D. Plumlee

Center for Coastal and Ocean Mapping

The Data Visualization Research Lab at the Center for Coastal and Ocean Mapping is investigating how three-dimensional navigational displays can most effectively be constructed. This effort is progressing along multiple paths and is implemented in the GeoNav3D system, a 3D chart-of-the-future research prototype. We present two lines of investigation here. First, we explore how tide, depth, and planning information can be combined (fused) into a single view, in order to give the user a more realistic picture of effective water depths. In the GeoNav3D system, 3D shaded bathymetry, coded for color depth, is used to display navigable areas. As in …

Electronic Chart Of The Future: The Hampton Roads Project, Rick Brennan, Colin Ware, Lee Alexander, Andy Armstrong, Larry A. Mayer, Lloyd C. Huff, Brian R. Calder, Shep M. Smith Lt, Matthew D. Plumlee, Roland J. Arsenault, Gerd Glang

Center for Coastal and Ocean Mapping

ECDIS is evolving from a two-dimensional static display of chart-related data to a decision support system capable of providing real-time or forecast information. While there may not be consensus on how this will occur, it is clear that to do this, ENC data and the shipboard display environment must incorporate both depth and time in an intuitively understandable way. Currently, we have the ability to conduct high-density hydrographic surveys capable of producing ENCs with decimeter contour intervals or depth areas. Yet, our existing systems and specifications do not provide for a full utilization of this capability. Ideally, a mariner should …

Marine Information Objects (Mio) And Ecdis: Concept And Practice, Lee Alexander

Center for Coastal and Ocean Mapping

Marine Information Objects (MIOs) consist of chart- and navigation-related information that supplement the minimum information required by ECDIS to ensure safety of navigation at sea. As related to the use of Electronic Navigational Chart (ENC) data, MIOs are additional, non-mandatory information not already covered by existing IMO, IHO, or IEC standards. Such information includes ice coverage, tide/water level, current flow, meteorological, oceanographic, and marine habitats. A Harmonization Group on MIOs (HGMIO) has been established between IHO and IEC to recommend additional data and display specifications that may be incorporated into future editions of IHO and IEC standards. This paper discusses …

Providing The Third Dimension: High-Resolution Multibeam Sonar As A Tool For Archaeological Investigations - An Example From The D-Day Beaches Of Normandy, Larry A. Mayer, Brian R. Calder, J S. Schmidt, C Malzone

Center for Coastal and Ocean Mapping

In general, marine archaeological investigations begin in the archives, using historic maps, coast surveys, and other materials, to define submerged areas suspected to contain potentially significant historical sites. Following this research phase, a typical archaeological survey uses sidescan sonar and marine magnetometers as initial search tools. Targets are then examined through direct observation by divers, video, or photographs. Magnetometers can demonstrate the presence, absence, and relative susceptibility of ferrous objects but provide little indication of the nature of the target. Sidescan sonar can present a clear image of the overall nature of a target and its surrounding environment, but the …

Optically Stimulated Luminescence Dating Supports Central Arctic Ocean Cm-Scale Sedimentation Rates, Martin Jakobsson, Jan Backman, Andrew Murray, Reidar Lovlie

Center for Coastal and Ocean Mapping

This paper presents new results from Optically Stimulated Luminescence (OSL) dating on a sediment core raised from the crest of the Lomonosov Ridge in the central Arctic Ocean. There has been much debate about dating sediment cores from the central Arctic Ocean and by using an independent absolute dating technique we aim to test whether or not relatively fast, cm-scale/ka, sedimentation rates were typical of Arctic’s Pleistocene depositional mode. On the basis of mainly paleomagnetic reversal stratigraphy, many previous studies suggest mm-scale/ka sedimentation rates. A common feature in these studies is that the first down core paleomagnetic negative inclination is …

Automatic Statistical Processing Of Multibeam Echosounder Data, Brian R. Calder

Center for Coastal and Ocean Mapping

This paper presents the CUBE (Combined Uncertainty and Bathymetry Estimator) algorithm. Our aim is to take advantage of statistical redundancy in dense Multibeam Echosounder data to identify outliers while tracking the uncertainty associated with the estimates that we make of the true depth in the survey area. We recognise that a completely automatic system is improbable, but propose that significant benefits can still be had if we can automatically process good quality data, and highlight areas that probably need further attention. We outline CUBE and its associated support structures, and apply it to a dataset from Woods Hole, MA, USA. …

A World Class Ecdis Laboratory, Darrell H. Smith, Lee Alexander

Center for Coastal and Ocean Mapping

No abstract provided.

Seafloor Segmentation Based On Bathymetric Measurements From Multibeam Echosounders Data, Yuri Rzhanov, Randy G. Cutter Jr., Larry A. Mayer

Center for Coastal and Ocean Mapping

Bathymetric data depicts the geomorphology of the seabottom and allows characterization of spatial distributions of apparent benthic habitats. The variability of seafloor topography can be defined as a texture. This prompts for the application of well developed image processing techniques for automatic delineation of regions with clucially different physiographic characteristics. In the present paper histograms of biologically motivated invariant image attributes are used for characterization of local geomorphological feahires. This technique can be naturally applied in a range of spatial scales. Local feature vectors are then submitted to a procedure which divides the set into a number of clusters each …

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 …

The Grounding Of An Ice Shelf In The Central Arctic Ocean: A Modeling Experiment, Martin Jakobsson, M Siegert, Mark Paton

Center for Coastal and Ocean Mapping

A numerical ice sheet model was used in a first test towards evaluating the hypothesis that, during a period of large-scale glaciation, an ice shelf emanating from the Barents/Kara Seas grounded across parts of the Lomonosov Ridge to a depth of around 1000 m below present sea level (Jakobsson, 1999; Polyak et al., 2001). Despite that we not include complex ice shelf physics or grounding line mechanics in our model and treat the process of marine melting in a simple manner, our experiments are the necessary first steps toward providing a comprehensive reconstruction of the former ice-sheet/ice-shelf system in the …