Coakley, B., D. N. Chayes, et al. (2004). "Design and Planning for an Arctic Ocean Observatory on the Beaufort Shelf." EOS Trans. AGU 85(47): Fall Meet. Supply.
Evidence is mounting that a complex suite of interrelated atmospheric, oceanic, and terrestrial changes are now underway in the arctic, affecting every part of the polar environment. Such changes are consistent with global climate modeling studies that consistently show the arctic to be one of the most sensitive regions to climate change. Understanding and quantifying these changes is complicated by the lack of time series data from the circum-arctic environment. Study of the Arctic Ocean is limited by sea ice and harsh weather that restrict access through much of the year. These constraints limit data acquisition and distort understanding of events, processes and biology of most of the Arctic Ocean. Without these data, it will not be possible to predict future change or the consequences of change. The Study of Arctic Environmental Change (SEARCH) program will develop capabilities for environmental monitoring, but cabled observatories are not now part of SEARCH. The planned Barrow Global Climate Change Research Facility will include a slant-drilled seawater intake, extending from on shore to beyond the ice gouge zone on the Beaufort Shelf. A cable could be routed through this intake to connect seafloor instrumentation to science support facilities in Barrow. In conjunction with existing facilities in Barrow that monitor the atmosphere and ocean surface, a seafloor observatory would permit study of the coupling between atmospheric and oceanographic processes and offer unique opportunities for research, environmental monitoring, education and the Barrow community. The proposed observatory could substantially augment SEARCH by collecting time series data on many processes and variables encompassing both regional and basinwide length scales. For example, the larger spatial scales might be sampled using acoustic tomography and AUVs, while the highly variable shelf environment could be sampled from cabled moorings containing a variety of sensor systems. These measurements, combined with surface observations from Barrow, would open a window on the shelf, its biology, oceanography and geology. The data collected from these sensors, available in realtime over the Internet would be an outstanding educational resource as well.
Chayes, D. N. and D. Forcucci (2004). "An Update on USCGC HEALY (WAGB-20) and its Capabilities." EOS Trans. AGU 85(47): Fall Meet. Supply.
The USCG Healy (WAGB-20) is the US academic research vessel supporting arctic research. The Healy's keel was laid at Avondale shipyard in 1996. An extensive science evaluation coordinated by the UNOLS Office was conducted in 2000. The first science legs were conducted in 2001 and the status of the Healy was reported by Swift et. al (2002) in EOS. Since then the UNOLS Arctic Icebreaker Coordinating Committee has worked with the Coast Guard, the ship, the National Science Foundation and the user community to encourage a number of significant improvements which have been made to the vessel including substantial upgrades to the science data acquisition and logging system, installation of a significantly improved science seawater system, installation of a dual frequency echo sounder with swept (Chirp) subbottom capability replacement of the 300 KHz ADCP with a 75 KHz broad band ADCP, substantial upgrades to the ship's satellite data receiving system and numerous communication system upgrades. Future upgrades in various stages of planning include upgrades to the lab spaces for improved efficiency and space utilization, improvements in the climate control chambers, more cooling water for incubators, upgrade or replacement of the multibeam seafloor mapping system, improved high latitude communications, and enhancements to the data acquisition, quality control and real-time monitoring capabilities among other things.
Chayes, D. N., R. A. Arko, et al. (2004). "Data Management for the Ridge 2000 Program." Eos Trans. AGU 85(47): Fall Meet. Suppl.
Since the start of this effort (September 1, 2003) we have developed a data base schema, selected and installed a relational data base management system (PostgreSQL), designed, developed and, deployed a draft set of metadata forms, ingested data from ten Ridge2000 cruises as of September 2004 and deployed a web accessible Ridge2000 data portal: http://www.marine-geo.org/ridge2000/ . At the portal, one can get content using with pre-constructed queries for survey targets and deployed instruments at each of the R2K Integrated Study Sites. Alternatively, our data link allows spatial, temporal and keyword searches to identify and download data. The current metadata forms have been used for 6 cruises and we have received constructive feedback (in addition to the actual metadata) from all three R2K integrated study sites. We are working on incorporating this feedback into an updated set of forms which we expect to release early in 2005. Other recent include substantial improvements to GeoMapApp, links to other data repositories, a major update of our web site, integration with data from Arctic, Antarctic, Margins data sets and the pre-constructed queries on the R2K portal page. Our plans for 2005 include: A second major revision of the metadata forms in early '05, improvements in the metadata ingestion process, enhanced authentication using LDAP, continued active participation in the broader data community developing interoperability as well as implementing direct interoperability with a number of complementary databases including the underway geophysical and multibeam databases at National Geophysical Data Center, the National Deep Submergence facility at Woods Hole, the Geological Data Center of the Scripps Institute of Oceanography, and the databases of the ODP (JANUS at TAMU, and Borehole Geophysics at LDEO)
Arko, R. A., S. M. Carbotte, et al. (2004). "An Integrated Data Management System for Marine Geoscience Research." Eos Trans. AGU 85(47): Fall Meet. Suppl.
The National Science Foundation is currently supporting dedicated databases for the Ridge 2000, MARGINS, and U.S. Antarctic Programs. We are developing an integrated Marine Geoscience Data Management System (MG-DMS; www.marine-geo.org) which supports the full range of data types for all of these programs. Construction of a single system allows us to consolidate our hardware, software, and system administration infrastructure; work more efficiently; and focus greater resources on developing a unified metadata schema, controlled vocabularies, and interoperability with other databases. We have developed a Web-based client which offers forms-based search and download capability, and a Java$^{TM}$ application (GeoMapApp; www.geomapapp.org) which offers map-based exploration of multiple data sets and the capability to create custom grids and images. The MG-DMS supports data from a wide variety of disciplines (biological, geological, and physical/chemical oceanographic); types (both physical samples and sensor data); spatial and temporal resolutions; and processing grades (from raw field data through derived products). Metadata records and controlled vocabularies are maintained locally in a central catalog, while the data files themselves are referenced as URLs and may reside in any partner repository. Our hierarchical metadata schema consists of Entries (typically a cruise, flight, or traverse); Dives (deployments of a daughter platform); Lines (survey transects); Stations (discrete survey locations, typically where physical samples are collected); Parameters (data types); and Arbitrary Digital Objects (data files). We are also developing a Lightweight Directory Access Protocol (LDAP)-based authentication system for proprietary data access and user profile management. We are pursuing data interoperability with partner repositories including the Ocean Floor Petrology Database (PetDB) at LDEO, Seismic Processed Data Center (SDC) at UTIG, Ocean Drilling Program Database (Janus) at TAMU, National Deep Submergence Facility (NDSF) at WHOI, Geological Data Center (GDC) at SIO, and National Geophysical Data Center (NGDC). Levels of interoperability range from URL referencing of remote data files (basic) to exchange of XML metadata records (intermediate) to Web Feature and Coverage Services (advanced).
Arko, R. A., K. A. Kastens, et al. (2004). DLESE and Ridge 2000 - Linking Research with Education. NSDL (National Science Digital Library) Annual Mtg., Chicago.
The Ridge 2000 Education & Outreach Plan (Goehring, 2002) calls for a multi-faceted effort to increase awareness and understanding of mid-ocean ridge science among educators and students. We are developing a collection of Ridge 2000 "Data Tips", a term coined by the National Marine Educators' Association (NMEA) for individual lessons or student activities built around real ocean science data sets. The data sets are carefully selected and the guidance through them is carefully constructed, such that students can extract fundamental insights about the ocean from the data. Our effort brings together Ridge 2000 scientists, technical, and outreach staff; science education doctoral students from Teachers College; K-12 science teachers; and scientist/ educators teaching at the undergraduate level. Workshops in the summers of 2004 and 2005 will follow the format developed by the DLESE (Digital Library for Earth System Education) Data Access Core Services group (DLESE, 2003).
Saleh, R., D. Chayes, et al. (2003). Grand Canyon Monitoring Research Center: Survey Protocol Evaulation Program. Flagstaff, Az, Grand Canyon Monitoring Research Center, USGS: 51.
DEFINITION
This document reports the findings of the peer review panel commissioned by the Grand Canyon Monitoring Research Center (GCMRC) for the Survey Protocol Evaluation Program (PEP).
These protocols are employed by the GCMRC Survey Department. The mission of the Survey Department is to provide support to GCMRC scientists and investigators for spatially referencing data collected in the field. In addition, the Survey Department provides terrestrial and hydrographic base maps and maintains a network of survey control throughout the ecosystem.
PURPOSE OF THE PANEL
The mandate of this Panel was to assist GCMRC in identifying optimum design and procedures for implementing an efficient and effective survey program that supports longterm monitoring of natural and cultural resources in the Colorado River Ecosystem (CRE). The peer evaluation process included four specific tasks: 1) reviewing the technology, equipment, and methodology applied by GCMRC; 2) introducing new technology to reduce the impact of scientific field work in the Canyon corridor; 3) examining spatial data collected by GCMRC to ascertain whether user needs are being met; and, 4) recommending alternatives.
SCOPE
The scope of this mission included review of terrestrial and hydrographic survey data collection methods and processing, data archiving, accuracy requirements and error determination, quality control and quality assurance, documentation and record keeping, spatial data standards, and survey control networks for both conventional (land based) and remotely sensed (airborne) survey data collection.
The scope further included requirements for spatially referencing and assessing aerial acquisition and other remotely sensed data sets. The review also covered requirements for automated spatial data processing methods using a geographic information system, image processing, and softcopy techniques for mapping and change detection of natural and cultural resources.
In addition, since the impact of science in the Grand Canyon represents a main concern, GCMRC aims at expanding the geographic extent of monitoring in a least impacting, yet in a cost effective manner. Therefore, the scope was extended to review the acquisition and processing protocols of aerial and other remotely sensed data sets intended for seamless integration with land-based survey data.
Chayes, D. N. (2003). Toward Quieter Sonars. Multibeam Workshop, Bremerhaven, Germany.
The designs of most, if not all, active sonars currently deployed incorporate the tenant that maximizing source level is one of the most effective techniques for maximizing signal to noise and hence performance.
Our community is feeling the impact of public concern and growing legal pressure that results from the fundamental lack of understanding of how active sonars (and noise) might impact marine mammals. This concern has already changed the way we operate some of our active systems. It is at least possible that this pressure will increase for the foreseeable future and may expand to incorporate a broader range of systems, sources and frequencies.
Efforts currently underway will eventually produce a much better understanding of animal physiology and sociology from which we can develop and implement realistic regulations and procedures for use of active sonars and sources. Public outreach, education, and the legal aspects of this puzzle are all currently being pursued.
In parallel, we need to actively pursue research and development into the reduction of source levels of acoustic survey systems. One logical approach to this issue is to evaluate the potential of coded pulse and other methods to achieve significant signal processing gain in the receiver. Substantial theory and experimental work already exist upon which such an effort could build. A successful implementation would enable significant reduction in the source level of the transmitter while maintaining current levels of performance and may provide the key to continued survey operations in some situations.
The capabilities required for a successful implementation are likely to result in a system that would be significantly more frequency-agile than existing designs. With suitable coded transmission pulses it should be possible to extend the capabilities to include multiple pings in the water. Such capability would substantially improve along track sampling. Should it turn out that we do not have to operate at reduced power, the improved processing would enable substantially improved performance while transmitting at full power.
With regard to a working implementation of a deep-sea multibeam that might evolve from this effort, one can foresee multiple modes of operation, including one where a maximum allowable source level is set and the system automatically (and/or with user guidance) adjusts other parameters such as swath width, transmit coding, and receiver gains to achieve the best performance under the existing conditions of ambient noise, seafloor reflectivity and sea conditions
Arko, R. A., D. N. Chayes, et al. (2003). "Development of a Rapid, Standardized Data Inventory for R2K Field Programs, Abstract B12A-0725." Eos Trans. AGU 84(47).
Effective data management for Ridge2000 requires the production of a complete data inventory for every field program in a timely and standardized way. We are developing a set of forms to document 1.) basic field program information (dates and locations, platform, science party, etc); 2.) an inventory of sensor systems, data types (marine geophysical, physical and chemical oceanographic, rock and sediment samples, and biological), and file formats; 3.) supplemental attachments (written reports, instrument diagrams, etc); and 4.) a basic navigation track. We regard this as the minimal set of metadata which should be produced immediately at the end of a field program, in order to publicize it in an online database and satisfy agency requirements. We have developed a prototype set of Portable Document Format (PDF) forms which can be completed during a cruise through a combination of manual and automated input. PDF is a stable and widely-used format, with software available as both a commercial product (Adobe Acrobat) and an open-source library (http://www.pdflib.org). Completing a PDF form requires only the Acrobat Reader software, which is freely available for every major computing platform. Acrobat offers extensive functionality to aid in data inventory, including the ability to verify content on-the-fly, import data from other files and forms, show controlled vocabularies as pop-up menus, export to XML format, and print a high-quality readable report. Prototype forms have been tested on a recent transit of the CGC Healy, and we plan to continue testing on other ships and soliciting community feedback over the next several months. We envision a long-term plan in which a master set of forms is deployed with every R2K field program, along with a copy of Acrobat Reader, on lightweight storage media such as USB keys. The completed forms will then be transmitted to the data management center, where they are ingested automatically and the information made available in the online R2K database.
Anderson, R. M., D. Chayes, et al. (2003). "Seafloor Sounding in Polar and Remote Regions, Abstract OS42A-0831." Eos Trans. AGU, Fall Meet. Suppl. 84(47).
Accurate and detailed knowledge of global bathymetry is a prerequisite for progress in numerous scientific disciplines related to earth systems. Among these are modeling of ocean circulation and its relation to climate; modeling of tides and tsunamis; describing tectonic plate structure and dynamics; understanding the formation, modification and ultimate destruction of Earth's crust; sediment transport, distribution, and thickness; paleoceanography; etc. Detailed understanding of seafloor shape and features is also necessary to select sites and routes for undersea communication cables. Detailed bathymetry is required to understand the energy and mineral potential of the seas. In two specific areas of the world oceans - the Arctic Ocean and the Southern Ocean - the existing database of bathymetry is too sparse to meet science needs. The Seafloor Sounding in Polar and Remote Regions (SSPARR) project intends to fill the bathymetry data gaps in both polar regions, by the development and deployment of unmanned drifting depth sounders with satellite telemetry. Each SSPARR buoy will incorporate a single-beam depth sounder, capable of reliably measuring ocean depths up to 5000 meters or more; a GPS receiver for geographic position determination; and a bi-directional satellite communication link for telemetering data to a shore site and for receiving commands from the shore site. A buoy control processor will receive and implement commands from the shore site; sample and archive GPS position data; initiate the depth sounding function and archive resultant data; monitor status of various buoys sensors; and respond to polling requests from the shore site by telemetering requested data. The buoy will be battery powered, with sufficient power to operate for several years (although in harsh polar environments, damage from sea ice may shorten the buoy lifetime.) With its GPS receiver and subsurface acoustic system, the SSPARR buoy may also be programmed to act as an aid to navigation for underwater vehicles, by transmitting position and time information to those vehicles by acoustic modem. A three year development is planned for the SSPARR depth sounder and buoy: In the first year, assessment and demonstration of technology required for the system is planned - a low power depth sounder capable of reliably and autonomously determining seafloor depths up to 5000 meters, integrated with a combined data acquisition, navigation, control, and telemetry system. Initial development of components of the shore site, including communication protocols, will also be accomplished in the first stage of SSPARR development. In this paper, we will present the conceptual design of the SSPARR depth sounder and buoy, and results of development and testing to date. An overview of the planned development activities leading to buoy production and system operational capability will also be presented.
Schmidt, V. E. and D. N. Chayes (2002). Arctic Acoustic Positioning System for Submerged Vehicles. Instrumenation for Arctic Ocean Exploration: Technology for Accessing the Water Column and Seafloor, Monterey, CA.
Experience conducting research with the US Naval submarine fleet and other Arctic endeavors has shown that both manned and unmanned submarine vehicles operating in Arctic waters for extended periods suffer from significant navigational inaccuracies. Ice cover prevents these systems from acquiring GPS or other fixes to correct inertial systems that have drifted. Ice camp and ship support is limited to their respective immediate areas.
For the Naval submarine fleet and the research conducted aboard these ships, correcting navigational inaccuracies translates to days of lost time. Locating surfacable features and obtaining GPS fixes requires on the order of 12 to 48 hours or longer - a significant portion of a 40 day cruise if it must be repeated weekly.
To provide navigational information to submarines, AUVs, rovers, and other sensors operating in the Arctic, small self deploying buoys containing GPS receivers and a simple transducer/acoustic modem could be launched from airplanes over wide areas. Time synchronized with the GPS time standard, a buoy could transmit its location exactly on the minute. Vehicles in the area could, in turn, get a bearing and range to determine their own position. The result would be an effective extension of the Global Positioning System to subsurface operations in the Arctic.
Schmidt, V. E., D. N. Chayes, et al. (2002). "Performance Evaluation of INMARSAT Fleet 77 Services Aboard the R/V Ewing." Eos Trans. AGU Fall Meet. Suppl., Abstract OS62B-0267 83(47).
Chayes, D. N. (2002). Basin-Scale Autonomous Vehicles. Instrumenation for Arctic Ocean Exploration: Technology for Accessing the Water Column and Seafloor, Monterey, CA.
The Arctic basin is among the least explored realms on Earth. Many of the classic methods developed for studying the Earth?s other basins are inefficient and/or impractical in this ice-covered basin. Reconnaissance scale mapping of the bathymetry, gravity field and shallow sub-surface sediments from nuclear submarines (in the SCICEX program) has provided significant new insights in the small percentage of the basin that has been explored. These results have raised as many new questions as they answered.
Substantial portions of the deep basin and virtually all of the shelves remain explored for want of suitable tools. While the possibility of future use of submarines should not be discounted, and existing autonomous vehicles are too small, we need to be working toward large (~10m by 4m by 3m) long range (10,000 km), long duration (weeks) autonomous vehicles. Such a vehicle is certainly attainable in the five-year time frame and could support multiple simultaneous instruments that would enable serious mapping of the seafloor and synoptic views of the water column.
In addition, such a large vehicle could act as a "mother-ship" for small (Remus) or medium (Dorado/Bluefin/ABE) sized vehicles to transport them to and from areas where detailed, near bottom survey and/or sampling programs are necessary.
Chayes, D. N. and V. E. Schmidt (2002). "Precision Positioning for Shallow Water Drilling." Eos trans. AGU Fall Meet. Suppl., Abstract PP21B-0330 83(47).
The science-driven requirement for sediment cores on continental shelves has led to the Active Heave Compensation (AHC) upgrade Global LAke Drilling (GLAD)-800 drilling system. The AHC-GLAD800 drill rig was developed for installation on the largest vessels in the UNOLS fleet and was tested in the November 2001 on the R/V Knorr. Evaluation of the results of that test cruise pointed out the need for a significant increase in the accuracy and repeatability of the real-time navigation input to the vessel?s dynamic positioning (DP) system. An shore-based evaluation of different Global Positioning System (GPS) receivers including P-Code, US Coast Guard broadcast differential GPS (DGPS) and commercial satellite distributed DGPS was used to develop an approach for real-time system that flags and excludes outliers in order to maintain the tight input requirements for the DP system. Analysis of the data collected from the shore-based experiments and the at-sea field program will be presented.
Chayes, D. N. and R. A. Arko (2002). "Real-time Metadata Capture Implementations." Eos Trans. AGU Fall Meet. Suppl., Abstract OS62B-0251 83(47).
The current rate of data acquisition in the ocean sciences precludes the manual generation of appropriate metadata after the fact. Recognizing this fact, we have begun to implement methods for creating metadata and inserting them into relational databases in real-time. We have also created web-based tools for watchstanders and maintenance personnel to enter logbook data in real-time. Several examples will be addressed in this poster. Enhancements to the Hudson Interactive River Observatory (HIRO) real-time data logging system have been made that create metadata records and insert them (as SQL transactions over a secure wireless TCP/IP connection) into a relational database in real-time. These records document the start and stop time of individual data files, of sensor-specific data streams and of the logging system as a whole. An interactive watchstanders logbook has been developed and used on the R/V Maurice Ewing to create and log metadata records associated with upgrades to the Hydrosweep DS2 multibeam system. A similar version of this tool is being used to capture the maintenance and update records associated with the HRIO system.
Caress, D. W. and D. N. Chayes (2002). "Processing, Archiving, and Disseminating Large Swath Mapping Datasets Using MB-System." Eos Trans. AGU Fall Meet. Suppl., Abstract OS61C-07 83(47).
MB-System is an NSF and MBARI-funded open source software package for the processing and display of swath mapping sonar data. Version 5.0 of MB-System is structured to enable the management of large datasets. The new software integrates editing and analysis tools with a single program, mbprocess, which outputs processed data files. This parallel approach now allows processing to proceed in a more flexible, efficient fashion. An additional important benefit is that the data management structure allows the active processing environment to be embedded within the overall data archive. Within this structure, bathymetry grids, sidescan mosaics, maps, images, GIS layers, and other data products are generated using the most up-to-date processed data. If one layers data dissemination tools and environments on top of the data archive, the served data products will also automatically reflect the latest processing efforts. MBARI, L-DEO, and NOAA-NOS are currently developing web-served swath data archives that use MB-System for processing, data product generation, and low-level data management. The aims of these efforts vary, and are reflected in differing high-level data server architectures. We will present and discuss the current state of these swath data archives.
Arko, R. A. and D. N. Chayes (2002). "A Web-Based Geospatial Metadata Browser, Abstract OS61C-07." Eos Trans. AGU Fall Meet. Suppl. 83(47).
We are developing a simple Web-based browser for the search and display of earth science metadata. Our design goals are: 1. to permit both map-based (geographical) and forms-based (textual) searching; 2. to integrate a wide variety of data types in a hierarchical fashion; 3. to conform to the FGDC metadata standard; 4. to take advantage of existing open source software wherever possible; 5. to be platform-independent, browser-independent, and "robust" (i.e. avoid application layers which are resource-intensive or behave unpredictably, such as Java applets); and 6. to present metadata in a dynamic fashion via live database connections. Our implementation is based on the MapServer GIS platform (developed at the University of Minnesota with NSF and NASA funding), PostgreSQL relational database management system, and PostGIS geographic database extensions (developed by Refractions Research Inc and available under GNU Public License). All of these packages are well-documented open source software and have been proven in commercial-grade applications. We combine geographical searching (click-and-drag on maps, in both global and polar projections) and textual searching (drop-down menus organized by FGDC category) for a range of geophysical, chemical, and biological data types. A corresponding framework for collecting and ingesting earth science metadata is reported elsewhere at this meeting (Chayes \& Arko, "Real-time Metadata Capture Implementations").
Taylor, B., A. Goodliffe, et al. (2001). "First Results from EW0108 Marine Seismic Survey of the Gulf of Corinth, Abstract T52A-0918." EoS Fall Meet. Suppl 82(47).
We report preliminary results from R/V MAURICE EWING cruise 2001-08 on which we imaged the bathymetry, stratigraphy and structure of the active rift in the Gulf of Corinth. Initial processing of the 240-channel seismic data (6- and 3-km streamer) through DMO and post-stack migration was performed onboard and ashore using ProMAX software. We also collected and processed swath bathymetry (Hydrosweep DS2) and free air gravity data. Deformation accompanying the 10-15 mm/yr stretching is focused beneath the Gulf of Corinth and causes major earthquakes. The bounding faults are high-angle near the surface but may, in the center of the Gulf, have low and perhaps very low dips in the seismogenic zone at 5-11-km depth. We sought, with 16.3-second MCS records, to directly image the fault geometry at depth, and thereby to distinguish between competing models of the deformation. Ongoing processing is aimed at suppressing the out-of-plane reflections from the basin margins in order to image the true reflectors at depth. We successfully recorded 8 long strike lines and 33 dip lines across the Gulf, providing the first systematic grid of seismic data that everywhere images to basement. Shots from the 8445 cu in 20-airgun array were also recorded by our regional array of 40 seismometers on land, plus ~30 existing stations, as well as by our two linear arrays of 75 (Derveni) and 25 (Itea) geophones.
Edwards, M., R. .Anderson, D. Chayes, B.J. Coakley, J.R. Cochran, M. Jakobsson, G. Kurras, L. Polyak, M. Rognstad (2001). "SCICEX sonars chart new topographies, new theories." Witness the Arctic 9: 1-2.
Chayes, D. N. and R. A. Arko (2001). "Open Clients for Distributed Databases." Eos Trans. AGU 82(47): Abstract OS11B-0375.
Chayes, D. N., N. Tervalon, et al. (2001). Ice Profiling Sonars: a Comparison of Error Budgets. Oceans 2001, Honolulu, HI, IEEE Ocean. Eng.
Chayes, D. N., A. Slagle, et al. (2001). "First Results From the (Multibeam) Hydrosweep DS2 Upgrade on the R/V Maurice Ewing, Abstract OS11B-0374." EOS Fall Meet. Suppl 82(47).
The ATLAS Hydrosweep DS multibeam swath mapping sonar system on the R/V Maurice Ewing was upgraded to a DS2 in May 2000. This upgrade increased the effective swath width from 59 beams over about 89 degrees to as many as 140 beams over approximately 118 degrees, added sidescan image as well as data records from which backscatter can be extracted. The upgrade replaced the outdated processing computer, half-inch tape drive and console with modern workstations and 4mm tape. The upgrade did not require changes to the under hull transducer arrays or transceivers so it was relatively inexpensive and was accomplished in a few days during a transit of the Panama Canal. Evaluation and software enhancements were done during subsequent transits. MB-System was enhanced to support the native, raw data format of the Hydrosweep DS2. We also expect to be able to support the more general SURF format that is also generated by new ATLAS sonar systems in the near future. In addition to the hardware and software upgrades to the multibeam, we installed a POS/MV-320 vertical reference system to take over from our venerable HIPPY-120 as the primary attitude reference for the Hydrosweep on the Ewing. The attitude data from the POS has allowed us to eliminate the turn rate restrictions and to improve the data quality. As an additional benefit the P-Code aided position data produced by the POS is significantly more stable and better behaved than our other navigation sources. The upgraded sonar was used during EW0108 (Taylor) in the Gulf of Corinth. As is usually the case with new implementations or modifications of complex systems, some unexpected behaviors were observed and carefully documented. Good remote support from the manufacturer enabled us to implement fixes and to generate very good quality bathymetry and sidescan images on board and in shore-side post processing. Two related software prototypes are currently being evaluated as part of this upgrade package. One is a web-based real-time watch standers logbook that facilitates the entry of standard log information directly into a relational database (rather than by hand on paper forms.) The second is a relational database that contains the FGDC metadata for multibeam swath bathymetry. This initial upgrade to our Hydrosweep establishes a stable base from which we expect to evolve significant new capabilities in the future. Some of these capabilities will be based on the unique cross fan capabilities of the Hydrosweep design.
Chayes, D. N., Arko, R.A (2001). "Open Clients for Distributed Databases: Abstract OS11B-0375." Fall Meet. Suppl. 82(47).
We are actively developing a collection of open source example clients that demonstrate use of our "back end" data management infrastructure. The data management system is reported elsewhere at this meeting (Arko and Chayes: A Scaleable Database Infrastructure). In addition to their primary goal of being examples for others to build upon, some of these clients may have limited utility in them selves. More information about the clients and the data infrastructure is available on line at http://data.ldeo.columbia.edu. The available examples to be demonstrated include several web-based clients including those developed for the Community Review System of the Digital Library for Earth System Education, a real-time watch standers log book, an offline interface to use log book entries, a simple client to search on multibeam metadata and others are Internet enabled and generally web-based front ends that support searches against one or more relational databases using industry standard SQL queries. In addition to the web based clients, simple SQL searches from within Excel and similar applications will be demonstrated. By defining, documenting and publishing a clear interface to the fully searchable databases, it becomes relatively easy to construct client interfaces that are optimized for specific applications in comparison to building a monolithic data and user interface system.
Caress, D. W., Chayes, D.N (2001). "Improved Management of Large Swath Mapping Datasets in MB-System Version 5, Abstract OS11B-0373." Eos Trans. Fall Meet. Suppl. 82(47).
MB-System is a NSF-funded open source software package for the processing and display of swath mapping sonar data. We are currently beta-testing a new release (Version 5.0) of MB-System which includes a substantially improved scheme for handling large datasets. In previous versions the MB-System tools each read a single input data file and generated a new output data file. This serial processing scheme generally produced a large number of intermediate data files. MB-System version 5 features the integration of the editing and analysis tools with a single program, mbprocess, that outputs processed data files. This parallel approach now allows processing to proceed in a more flexible, efficient fashion. Management of multiple large datasets in MB-System currently depends on the use of recursive lists of filenames and on the maintenance of a metadata file for each data file. This approach is effective for working with hundreds to thousands of swath data files, but becomes slow as the number of files increases to larger orders of magnitude. We are developing SQL based tools for inserting swath file metadata into relational databases and for providing simple, useful queries to such a database. In order to facillitate the use of relational databases, MB-System now supports the insertion of standard metadata tags into processed swath files and the routine extraction of those metadata. The initial list of swath data metadata tags has been developed jointly by MBARI, L-DEO, and SIO.
Arko, R. A., Chayes, D.N. (2001). "A Scalable Database Infrastructure, Abstract OS11B-0376." EOS Fall Meet. Suppl 82(47).
The rapidly increasing volume and complexity of MG\&G data, and the growing demand from funding agencies and the user community that it be easily accessible, demand that we improve our approach to data management in order to reach a broader user-base and operate more efficient and effectively. We have chosen an approach based on industry-standard relational database management systems (RDBMS) that use community-wide data specifications, where there is a clear and well-documented external interface that allows use of general purpose as well as customized clients. Rapid prototypes assembled with this approach show significant advantages over the traditional, custom-built data management systems that often use "in-house" legacy file formats, data specifications, and access tools. We have developed an effective database prototype based a public domain RDBMS (PostgreSQL) and metadata standard (FGDC), and used it as a template for several ongoing MG\&G database management projects - including ADGRAV (Antarctic Digital Gravity Synthesis), MARGINS, the Community Review system of the Digital Library for Earth Science Education, multibeam swath bathymetry metadata, and the R/V Maurice Ewing onboard acquisition system. By using standard formats and specifications, and working from a common prototype, we are able to reuse code and deploy rapidly. Rather than spend time on low-level details such as storage and indexing (which are built into the RDBMS), we can focus on high-level details such as documentation and quality control. In addition, because many commercial off-the-shelf (COTS) and public domain data browsers and visualization tools have built-in RDBMS support, we can focus on backend development and leave the choice of a frontend client(s) up to the end user. While our prototype is running under an open source RDBMS on a single processor host, the choice of standard components allows this implementation to scale to commercial RDBMS products and multiprocessor servers as appropriate. The same approach allows multiple parallel (peer) data base systems to be implemented and searched by remote clients.
Sambrotto, R. and D. Chayes (2000). The use of nuclear powered submarines for oceanographic research in ice covered regions. N'ocean 2000; International Workshop on Utilization of Nuclear Power in Oceans, Tokyo.
Cochran, J. R. and D. N. Chayes (2000). Project Report: Purchase of equipment to support the Lamont-Doherty Earth Observatory in participation in an exploration by sumarine of the basins of the polar seas. Palisades NY, Lamont-Doherty Earth Observatory of Columbia University.
Caress, D. W. and D. N. Chayes (2000). "Optimal Navigation Adjustment for Poorly Navigated Swath Bathymetry Surveys, Abstract T52C-14." EOS Fall Meet. Suppl 81(48).
AB: Swath bathymetry surveys conducted using sonars on towed platforms, ROVs, submersibles, and AUVs sometimes suffer from navigational errors that are large with respect to the lateral bathymetric resolution. MBnavadjust is a new public domain software package that: 1) Automatically identifies places where bathymetry swaths overlap or cross. 2) Displays the bathymetry of crossing/overlap points, allowing users to interactively determine the navigation offset required to match common features. 3) Inverts for an optimal navigation adjustment solution that fits the interactively determined crossing/overlap offsets while minimizing the first (speed) and second (acceleration) derivatives. 4) Automatically applies the navigation adjustment solution to the relevant swath data files. MBnavadjust will be distributed as part of MB-System, an NSF and MBARI supported public domain software package for the processing and display of swath mapping sonar data. Like all MB-System utilities, MBnavadjust supports a large number of data formats associated with many different multibeam and interferometry sonars. Examples to be presented include a deep-towed multibeam survey of Loihi Seamount, a deep-towed interferometry sonar survey in the Escanaba Trough, and a SCAMP submarine-mounted interferometry sonar survey in the Arctic. In both deep-towed surveys, the poorly navigated, high resolution near bottom surveys are adjusted relative to themselves and relative to lower resolution multibeam surveys by surface vessels.
Polyak, L., M. H. Edwards, et al. (1999). Glacial Scouring in the Deep Arctic Ocean: Evidence from the Chukchi Plateau and the Lomonosov Ridge. 1999 AGU Fall meeting, San Francisco, CA, AGU.
New data from the Chukchi Plateau and the Lomonosov Ridge
indicate a direct glacial impact on the Arctic Ocean bottom to
water depths of 1 km. Recent chirp-sonar data show an
erosional unconformity combined with rough seafloor at the
Lomonosov Ridge crest. Jakobsson [1999] infers a prominent
erosional event; however, it has not been possible from chirp
data to make a conclusive interpretation of the nature of this
erosion. Data obtained by the Sidescan Swath Bathymetric
Sonar (SSBS) during the SCICEX-99 cruise shed new light on
this problem. The rough surface of the eroded area on the
Lomonosov Ridge has a typical ice-scoured appearance, with
chaotically oriented ploughmarks of several meters deep
covering the entire area. These results unambiguously indicate
that a portion of the ridge crest at modern water depths down
to 1 km has been scoured by extremely thick floating ice
related to an extensive glacial event in the Arctic Ocean. Even
more diverse glacigenic bedforms were found at the Chukchi
Plateau, including morainic ridges at depths down to 600 m and
linear glacial-sole markings (flutes, drumlins) in the area
confined by the ridges. The SCICEX-99 data, combined with
earlier findings of deep-sea glacial scouring at the Yermak
Plateau, indicate that large portions of the Arctic Ocean have
been capped by a floating ice sheet, similar to the Ross Ice
Shelf in Antarctica, at least once in the Pleistocene. Further
studies are needed to understand whether there was one
event or multiple glacial events of this magnitude and what was
its/their timing
Kurras, G. J., M. H. Edwards, et al. (1999). Tectonism and Volcanism Along the Gakkel Mid-Ocean Ridge [5E-74 E]: Initial Processing and Analysis of SCAMP Sidescan Data from SCICEX `98 and `99. 1999 AGU Fall meeting, San Francisco, CA, AGU.
The Gakkel Mid-Ocean Ridge (MOR) is the slowest spreading
center on the planet with full-spreading rates between 1.33
cm/yr along the Greenland end to 0.63 cm/yr along the
Siberian end. Connected to the Knipovitch Ridge by the
Spitzbergen transform, the ridge continues northeast through
the center of the Eurasian basin before terminating into the
Laptev shelf. Aeromagnetic surveys reveal relatively straight
continuous magnetic lineations indicating an active MOR with
organized symmetric seafloor spreading since the ridge's initial
formation in the late Paleocene (apx 58mybp). In 1998 and
1999 a joint effort by the U.S. Navy and NSF resulted in two
SCICEX cruises acquiring geophysical data along the Gakkel
Ridge in an effort to examine the nature, origin, and evolution
of the Eurasian basin. The Arctic cruises, onboard the USS
Hawkbill, utilized a newly designed geophysical survey system
called SCAMP (Seafloor Characterization And Mapping Pods)
to simultaneously acquire gravity, sidescan, swath bathymetry,
and chirp sub-bottom profiler data. These data represent the
first detailed examination of the basic structure, morphology
and history of the Gakkel Ridge. The SCICEX 98 cruise
surveyed to 50 km on either side of the Gakkel Ridge axis for
200 km along two discontinuous segments of the ridge
[27\deg-49\deg E \& 52\deg-74\deg E]. The SCICEX 99 cruise
returned to fill in and extend the 1998 survey for complete
coverage to 50 km on either side of the ridge axis
[5\deg-74\deg E]. The combined survey images seafloor to
about 8.5 Ma in age, covering a range of spreading rates from
1.0 to 1.3 cm/yr. The sidescan data collected by the SCAMP
survey are used to map volcanic and tectonic features along
the Gakkel Ridge axis and flanks. Where possible, variations in
sidescan intensity have been used to map lava flow
distributions and estimate relative flow ages. Maps of flow
distributions are combined with SCAMP bathymetry and
magnetics data from previous published surveys to
characterize the neovolcanic zone. Statistical analyses of faults
in the axis and along the flanks are compared with analogous
results for the Mid-Atlantic and Southwest Indian Ridges to
document similarities and differences observed along the
Gakkel Ridge.
Johnson, P. D., B. Appelgate, et al. (1999). On-line access to SCAMP, HAWAII MR1 and Mesotech Sonar Data. 1999 AGU Fall meeting, San Francisco, CA, AGU.
During the SCICEX effort to use the Seafloor Characterization
and Mapping Pods (SCAMP), the National Science Foundation
(NSF) advised investigators responsible for reducing various
types of data that proprietary rights would be strictly limited to a
two year period and afterward the data must be publicly
available. The Hawaii Mapping Research Group (HMRG) had
already spent the better part of a year developing an online
website to make public domain HAWAII MR1 and Mesotech
data available to the general scientific community. In light of the
NSF announcement regarding the SCICEX data, it was decided
to modify the HMRG website to also include Arctic Basin
information. The HMRG online data archives are designed for
simple and swift operation using visual cues. Users can rapidly
navigate through the various systems and services currently
available from HMRG by simply clicking on buttons that will
direct the user to a particular piece of information. For
instance, on the HAWAII MR1 pages users can choose from a
variety of map sets simply by clicking on the button for a
particular chart which then allows the user to download high
resolution sidescan and bathymetry maps to their own
machine. The web site also provides access to data processing
documentation, shipboard operations logs, and system
software. Data that are considered proprietary (such as
federally funded research within two years of acquisition) are
password protected to restrict access to PIs and their
designates. The EPR data archives website provides a variety
of views of the East Pacific Rise between 9\deg and 10\deg N.
Data range from the regional views of the area to the
small-scale, and include Seabeam maps, high-resolution
bathymetric maps of vent locations derived from Mesotech
sonar data, and digital photographs of individual hydrothermal
vents. To alleviate the user from slogging through many levels
to reach the data of interest, html frames and customized
pull-down menus have been designed to allow the EPR
archives to be rapidly negotiated. SCAMP data are presently
still proprietary and therefore are password protected. Once
access has been gained to these archives, users will find
bathymetric and sidescan maps for various charts as with the
HAWAII MR1 archives. Because SCAMP is a unique instrument
and processing is still underway, there are also examples of
different data processing approaches and comparisons of data
in various stages of production.
Goemmer, S. A., R. M. Anderson, et al. (1999). SCAMP Submarine Installation Basics. AGU, Fall 1999, San Francisco, American Geophysical Union.
The SCAMP installation was designed to assure optimum system performance, maintain ship performance, and assure
personnel safety. Identification of external equipment locations
was critical because hull attachment, cabling, and serviceability
posed the biggest challenges. System performance was
optimized by selecting the best operating position on the hull,
maintaining appropriate separation from ship's systems, and
properly orienting sensors. For this bottom-mapping system,
keel mounted sensors were used to minimize hull interference
and maximize sensor performance. Sensor orientation was
symmetrical. Also, attachment was simplified because roll was
zero and pitch was small. Two hull-mounted structures, each
consisting of a foundation and pod, were made - one for a
Sidescan Bathymetric Sonar and one for a High Resolution
Subbottom Profiler. Each foundation provided a flat surface to
attach the pod while accounting for hull curvature and ship
frame locations. Attachment points were located at frame
locations to avoid possible hull distortion. The attachment
technique involved welding cylindrical mounting pads, each with
a tapped hole, to the hull. Below-the-waterline welding and
anechoic tile removal required drydocking the submarine
because of the precision required. A skirt was attached to the
foundation to ensure no gaps between the foundation and hull
existed. These gaps could have caused hydrodynamic noise.
Each pod housed the sensors in a hydrodynamic shape which
was readily removed from the foundation. The pods were
designed to have "tear drop" shapes where the length is at
least four times the pod's width to minimize hydrodynamic
noise. The pods were located near the submarine's forward
main ballast tanks (MBTs) to simplify cable routing. MBTs, as
well as free flood areas such as the sail, typically have
wireways, electrical hull penetrators, and bulkhead penetrators
located within them servicing various ship systems. The cables
were routed in to the MBTs by cutting holes in the
non-pressure hull at the bottom of the MBTs thereby avoiding
rising the MBT residual waterline. Available space was utilized
in existing penetrators to avoid the cost and complexity of
replacing existing penetrators with new pentrators which
accommodate both existing cables and new cables.
Edwards, M. H., L. Polyak, et al. (1999). New Perspectives on the Chukchi Cap and Northwind Rise from SCICEX-99 SCAMP data. 1999 AGU Fall meeting, San Francisco, CA, AGU.
For seven days in April 1999 scientists and engineers aboard
the U.S.S. Hawkbill, a Sturgeon-class nuclear-powered
submarine, used the Seafloor Characterization and Mapping
Pods (SCAMP), an interferometric bathymetry and sidescan
swath mapping system (SSBS), high-resolution subbottom
profiler (HRSP), gravity meter, and data acquisition system, to
map the Chukchi Borderland. The primary goals of the survey
were to search for evidence that large ice sheets had eroded
shallower regions and to document the surface and subsurface
structure of the poorly mapped Chukchi Cap and Northwind
Ridge. SSBS data show that most portions of the Chukchi
Margin and Chukchi Cap less than $\sim$400 m deep are
dominated by iceberg ploughmarks. Just north of the Chukchi
Margin is an $\sim$8 km x 10 km field of subparallel lineations
that appear distinctly different from the adjacent ploughmarks.
On the southern side of the Chukchi Cap are a series of
narrow arcuate ridges that may be moraines or eskers. Another
field of parallel lineations, oriented approximately 45 degrees to
the field just north of the Chukchi Margin, was mapped on the
northern tip of the Chukchi Cap. Interspersed between the
ploughmarks and these larger fields of scours/moraines/eskers
are smaller regions containing drumlin-like features. Few
glacigenic features were mapped on the Northwind Ridge, but
the ridge itself was discovered to consist of a suite of large
rotated fault blocks. Relief on the steeper edge of one of the
rotated fault blocks exceeds 1 km over approximately the same
1 km distance. In sedimented-dominated basins adjacent to the
rotated fault blocks both sidescan and bathymetry data show
evidence of mass wasting. A 300-400 m high, $\sim$5 km wide,
round, flat-topped seamount is located between fault block
ridges. The seamount plateau and flanks are heavily
sedimented, but it is possible to discern a crater in the summit
plateau and at least one constructional cone at the base of the
seamount. Bathymetry data depict what may be another
constructional feature north of the seamount. By combining
these preliminary findings from the bathymetry data with
sidescan and gravity results, we plan to document the
extension that has been accomodated along the Northwind
Ridge.
Edwards, M. H., B. J. Coakley, et al. (1999). Arctic Basin Insights 1: New Data for the Amerasian Basin from SCICEX-99. 1999 AGU Fall Meeting, San Francisco, CA, AGU.
On March 18, 1999, the U.S.S. Hawkbill, a Sturgeon-class
nuclear powered submarine, left Pearl Harbor, Honolulu, for a
thirty-five day geophysical mapping and water sampling
program in the Arctic Ocean. The Hawkbill was equipped with
the Seafloor Characterization and Mapping Pods (SCAMP), an
interferometric bathymetry and sidescan swath mapping
system, high-resolution subbottom profiler, gravity meter, and
data acquisition system as well as a digital ice profiling system,
upward looking camera, and a suite of sensors for measuring
physical and biogeochemical properties of Arctic waters. On
four occasions during SCICEX-99, Hawkbill rendezvoused with
Ice Camp Lyon, established on the floating ice pack 130 miles
north of Barrow, Alaska, allowing seven civilian scientists and
engineers to accomplish myriad scientific goals. The first seven
days of the SCICEX-99 focused on mapping the Chukchi
Borderland, specifically the Chukchi Cap and Northwind Ridge.
During this survey SCAMP mapped the shallower portions of
the Chukchi Cap to search for glacigenic features that could
indicate whether an ice sheet, similar to the Ross Ice Shelf in
Antarctica, had once covered the Arctic Ocean. SCAMP data
showed that the shallowest portions of the Chukchi Margin and
Cap (less than $\sim$400 m) were dominated by iceberg
ploughmarks; however, in slightly deeper regions (400 - 600 m)
SCAMP mapped glacial flutes, drumlins and ridges that may be
moraines or eskers. The Northwind Ridge showed little
evidence of glacial erosion, but was discovered to have a
complex longer wavelength morphology dominated by a suite of
three large rotated fault blocks. In the midst of these fault
blocks is a 300-400 m high, round, flat-topped seamount. The
seamount is heavily sedimented, indicating that it has been
inactive for some time, however, it is still possible to discern a
crater in the summit plateau and at least one constructional
cone at the base of the seamount. The second scientific leg of
SCICEX-99 was a five day survey designed to sample the
Beaufort undercurrent and map corresponding portions of the
Alaskan margin. SCAMP data for the extremely rugged terrain
at the western end of this survey depict a complex submarine
canyon system formed during the last glacial maxima. Toward
the eastern end of the survey, which approached the boundary
between the U.S. and Canadian EEZ's, the topographic
variability became considerably less pronounced and the
small-scale roughness of the seabed changed dramatically. An
extremely strong correlation between the longer wavelength
morphology and water properties in this region demonstrates
the significant role of seafloor topography in influencing Arctic
water mixing, which in turn influences the mass and distribution
of the polar ice pack and ultimately affects the global climate.
Davis, R. B., M. H. Edwards, et al. (1999). Processing SCAMP Swath Bathymetry and Sidescan Sonar Data. 1999 AGU Fall meeting, San Francisco, CA, AGU.
The Seafloor Characterization and Mapping Pods (SCAMP)
were mounted on the hull of the nuclear-powered
Sturgeon-class submarine, USS Hawkbill, to permit under-ice
geophysical mapping of the Arctic Basin during the SCICEX-98
and SCICEX-99 programs. SCAMP instrumentation includes a
sidescan swath bathymetric sonar (SSBS) operating at a
frequency of 12 kHz that was built by Raytheon Systems
Company. The sonar transducer arrays, designed specifically
for under-ice operation, have four rows of elements. Each row
is driven independently during transmit to allow beam steering;
the rows are combined during reception to simulate two virtual
array rows per side of the submarine. The SCAMP SSBS swath
bathymetry is computed from the phase difference between the
virtual rows; since the spacing of the virtual rows is almost one
full wavelength apart, phase ambiguities known as phase
"wraps" occur in the data. To correctly unwrap the phase data
and monitor system performance, the Hawaii Mapping
Research Group (HMRG) has created an acoustic processing
analyzer that displays the real and imaginary components of
the virtual arrays, as well as the magnitudes and phases
generated therefrom using settings that are controlled by data
processors. This interface facilitates visual fine-tuning of such
parameters as signal-to-noise thresholds, filter lengths and
bottom detect gates to quickly accommodate changes in the
water column or seafloor substrate. Building on an idea of C.
Nishimura at the Naval Research Laboratory, HMRG also
developed a graphical approach for generating the
angle-angle tables that are used with interferometric sonars to
convert acoustic phase angle differences to geometric angles,
thus producing bathymetry. Using these software packages
during the SCICEX-99 program, scientists were able to
generate maps of the shallow ($<$600 m deep) Chukchi
Borderland with bathymetric swath widths approximately ten
times greater than water depth. Sidescan processing of the
SCICEX-99 data is similar to that of other shallow-towed 12 Khz sonar systems with the notable exception of interference from
the SCAMP high-resolution subbottom profiler (HRSP) and the
submarine's own echo sounder which have not been
successfully removed using conventional despeckling and
destriping techniques. We are presently experimenting with a
number of other approaches for removing this interference,
including matched-filter processing, and will present our
findings in San Francisco.
Cochran, J. R., B. J. Coakley, et al. (1999). Structure of the Ultraslow Spreading Gakkel Ridge: Insights from SCICEX SCAMP Swath-Bathymetry and Gravity Data. 1999 AGU Fall Meeting, San Francisco, CA.
Spreading rates at the Gakkel Ridge in the Eurasian Basin of
the Arctic Ocean range from 0.6 to 1.3 cm/yr full-rate, making
this the slowest spreading mid-ocean ridge (MOR) on Earth. In
1998 the Seafloor Characterization And Mapping Pods
(SCAMP) were attached to the hull of the USS Hawkbill, a U.S.
Navy Sturgeon- class nuclear powered submarine, with the
goal of collecting swath bathymetry and sidescan,
high-resolution subbottom and gravity data for several
prominent features in the Arctic Basin including the Gakkel
Ridge. During the SCICEX-98 and SCICEX-99 deployments of
the Hawkbill more than twelve days of data were collected for
the Gakkel Ridge, providing $\sim$100\% bathymetric and
$\sim$200\% sidescan coverage of the western 600 km of the
ridge (total spreading rates of 1.15 to 1.3 cm/yr) to a distance
more than 50 km to either side of the ridge axis. A
reconnaissance survey of the ridge axis extended an additional
400 km to the east where the spreading rate is $<$ 1.0 cm/yr.
Preliminary data processing has not identified any transform
offsets along the entire mapped length of the Gakkel Ridge.
Segmentation appears to be accomplished by oblique
spreading segments and/or non-transform discontinuities of
less than about 20 km offset. As a result, the rift valley is quite
sinuous and experiences abrupt changes in width at some
locations. In spite of the lack of transforms, inside corner highs
are well developed with steep slopes and up to 3 km relief.
Outside corners are deep with low slopes. As a result, rift valley
morphology is often very asymmetric with the sense of
asymmetry changing along segments. The axial rift valley has
1500-1800 m of relief and reaches depths of 5200 m,
considerably greater than observed on the Mid-Atlantic Ridge.
Abyssal hills are large, blocky and commonly bounded by
500-1500 m scarps. Gravity studies [Coakley and Cochran,
1998] indicate that thin ($<$ 4 km) crust is characteristic of the
western Gakkel Ridge. However, the swath-bathymetry data
depict features with positive relief within the axial valley that we
interpret to be constructional volcanic morphology. The new
gravity data, combined with complete bathymetric coverage will
allow estimates of intrasegment variations in crustal thickness
and better definition of along-axis changes in crustal structure
related to the along-axis
Coakley, B. J., M. H. Edwards, et al. (1999). "Arctic Basin Insights 2: New Data for the Eurasian Basin and Lomonosov Ridge from SCICEX-99: Abstract T31F-09." EOS Fall Meet. Suppl 80.
After departing Ice Camp Lyon on April 16, 1999 the USS Hawkbill began a cross-basin acoustic propagation profile (ACOUS) of the Arctic Basin. Hawkbill followed this transect until encountering the Lomonosov Ridge. Running south over the highest part of the ridge, the SCAMP system mapped an extensively ice-gouged region characterized by small-scale relief. Three segments of contrasting internal structure were selected for geophysical mapping on the Lomonosov Ridge. The southernmost survey was run across a series of oblique, high-standing ridges. During the northbound transit to the central survey area the Hawkbill mapped the eastern side of the Lomonosov, repeatedly crossing the eastern flank. The central survey focused on the Amerasian side of the ridge, with track lines extending out to the abyssal plain. The northernmost survey of the Lomonosov focused on a closed basin in the center of the ridge which appears to be a single graben surrounded by narrow high-standing ridges. After some hours at the north pole the Hawkbill rejoined the ACOUS profile. Upon completing the ACOUS cross-basin transect Hawkbill transitted to the axis of the Gakkel Ridge where SCAMP was used to map: (a) the eastern Gakkel Ridge, extending complete coverage of the axial zone to seafloor formed at a full spreading rate of about 1 cm/yr, (b) a gap in data from the SCICEX 98 survey of the central Gakkel Ridge, and (c) the western Gakkel Ridge to the edge of the operational area. The combined SCICEX 98 and 99 datasets provide a comprehensive map of seafloor formed at the Gakkel Ridge with full spreading rates ranging from 1.0 - 1.3 cm/yr. There is coverage to 50 km on either side of the axis (corresponding to magnetic anomaly 5) over a region formed at full spreading rates ranging from 1.15 to 1.3 cm/yr. The striking characteristics of ridge morphology; deep axis, high relief and continuity of the axis observed in the 1996 and 1998 SCICEX surveys were also apparent in SCICEX 99 data. Upon completion of the Gakkel Ridge survey, a sediment drift deposit near the eastern tip of the Yermak plateau in the Norwegian EEZ was surveyed with permission of the Norwegian goverment. Two 90 km lines were run just east of the tip of the plateau; eight 48 km lines were run across a distinctive bench on the plateau's northern flank. The success of the SCICEX 99 cruise is in large part due to the crew and officers of the USS Hawkbill who have shown unfailing enthusiasm and support for the science objectives of the program. The commanding officer, CMDR Robert Perry, is due a great deal of credit for fostering this environment.
Coakley, B., J. Cochran, et al. (1999). Internal Structure of the Lomonosov Ridge and Location of the Continent-Ocean Boundary from SCICEX data. 1999 AGU Fall meeting, San Francisco, CA, AGU.
The Lomonosov Ridge is a long sliver of continental crust,
analogous to Baja California, that was rifted off the Barents
Shelf by the propagation of the Gakkel Ridge across the Arctic.
Data collected during SCICEX show a sinuous, continuous
ridge that spans the Arctic Ocean, dividing the Eurasian from
the Amerasian Basin. This contrasts with its map
representation in the GEBCO charts, which shows a narrow,
straight ridge with a substantial gap near the North Pole. The
combined gravity and bathymetry data have been used to
identify the location of a series of half-grabens that segment
the ridge into a series of high-standing en echelon blocks.
During SCICEX-99 SCAMP data were acquired across three
distinctive sections of the Lomonosov Ridge to document its
origins and relationships with adjacent extended continental
and oceanic crust in both the Eurasian and Amerasian basins.
Submarine tracks were arranged to provide $\sim$100\% swath
bathymetric coverage of the high ridge. The southernmost
survey (centered on 84 degrees N) mapped,a set of three
independent, linear ridges, separated by low lying underfilled
basins, trending obliquely to the overall trend of the ridge. This
portion of the Lomonosov Ridge is a much broader and more
complex structure than has been commonly recognized. The
central underfilled graben appears to extend to the north,
parallel to the eastern edge of the Lomonosov Ridge. The
easternmost underfilled basin may continue north, plunging
beneath the abyssal plain in the Makarov Basin. The second
survey (centered at about 87 degrees North) conducted over
the ridge mapped a large half graben and horst block. Here the
extensional structures appear to trend parallel to the ridge
itself. The third survey (centered at about 89 degrees North)
mapped a single central graben that can be observed as a
nearly enclosed, underfilled basin extending about 100 km
along the axis. While the continent-ocean boundary can be
clearly observed in aeromagnetic and gravity anomaly data on
the Eurasian side of the ridge, it is far less clear where to place
it on the Amerasian side. The broad extent of the ridge in the
southern survey area, as well as the extensional structures that
appear to step off the ridge, suggest that the Amerasian side of
the ridge may be characterized by an extensive region of
extended continental crust. Data acquired on SCICEX cruises
and recently declassified US Navy bathymetry data are now
sufficiently dense to put a limit on the minimum elevation of the
Lomonosov Ridge, which restricts mixing between the Eurasian
and Amerasian Basins. It appears that the ridge top is nowhere
deeper than 2000 meters.
Chayes, D. N., R. M. Anderson, et al. (1999). Seafloor Characterization and Mapping Pods (SCAMP): submarine-mounted geophysical mapping. OCEANS '99.
Chayes, D. N., R. M. Anderson, et al. (1999). "SCAMP Performance: Abstract T32B-25." EOS Fall Meet. Suppl 80.
The Seafloor Characterization And Mapping Pods (SCAMP) is an underway geophysical survey system designed for swath mapping and subbottom profiling from submarines. SCAMP was installed on the USS Hawkbill (SSN666), a US Navy Sturgeon-class attack submarine. Two deployments to the Arctic (SCICEX98 and SCICEX99) have now been completed and initial data processing is moving forward. This poster will present the results of our initial evaluation of the performance of the system, in particular the Sidescan Swath Bathymetric Sonar (SSBS) and the High Resolution Subbottom Profiler (HRSP). More information about SCAMP can be found at http://www.ldeo.columbia.edu/SCICEX/SCAMP The Sidescan Swath Bathymetric Sonar is a SeaMARC design adapted for operation under the arctic ice canopy and for installation and operation on a nuclear submarine. The SSBS provides sidescan imagery as well as bathymetry of the seafloor on both sides of the submarine's track. At altitudes less than 500 meters, features as small as 10 meters can be resolved in the inner half of the swath. Swath bathymetry in deep water was produced over 130 to 140 degrees. Sidescan swath widths in excess of 166 (ñ83 degrees) at altitudes of a few hundred meters were observed and swath widths of 16 to 18 km in water depths greater than roughly 1 km Altitudes derived from the SSBS data correlate very well with the HRSP altitudes and observations from the ship's own sounder. We attribute this extraordinary swath width to a combination of good design, low platform dynamics and the acoustically quiet platform. Several "flat bottom" calibration data sets were collected and quantitative comparisons will be presented. The High Resolutions Subbottom Profiler is an ODEC design adapted for installation and operation on a submarine. Although space considerations restricted us to a relatively small (3 by 3) element transducer array and a low power (2KW) transmitter there are occasions where the system produced penetration of up to 200 meters (at 1500 ms) of penetration into the bottom with sub-meter resolution. The very quiet stable submarine platform is a major contributor to this extraordinary performance.
Backman, J., B. Coakley, et al. (1999). "High Resolution Sub-bottom Profiler Data Collected During SCICEX 99 on Lomonosov Ridge; Mapping of Proposed Drill Sites." EOS Fall Meet. Suppl 80.
Seafloor sampling in the Arctic Ocean has been restricted by our lack of knowledge about the seafloor itself. Site surveys, which are required to plan ODP legs, cannot be conducted in the floating ice pack that covers most of the Arctic Ocean. The US Navy's nuclear-powered fast attack submarines employed by SCICEX have collected the first extensive set of swath bathymetry, backscatter and high-resolution sub-bottom profiler data obtained in the Arctic. These data have the potential support a number of seafloor sampling programs in the future, including the proposed ODP leg to the Lomonosov Ridge. The SCAMP High Resolution Sub-bottom Profiler (HRSP) is a modified version of a Bathy-2000P developed in close collaboration with Ocean Data Equipment Corporation. The HRSP transmits a frequency-modulated chirp from an array of nine elements mounted in a pod on the ship's keel. During this cruise a 50 millisecond linear sweep from 2.75 to 6.75 kHz was most commonly used. Except in a few cases the system was used at full power (2 kilowatts) at all times. Matched filter processing of the returned acoustic energy reveals the stratigraphy down to about 100 meters with a resolution of 20-30 cm. During SCICEX 99 SCAMP data was acquired across three distinctive sections of the Lomonosov Ridge to document its internal structure and relationships with adjacent extended continental and oceanic crust in both the Eurasian and Amerasian basins. A total of 35 new crossings of the ridge were obtained. Many lines extended from the abyssal plain in the Makarov basin to the abyssal plain in the flanking Amundsen Basin. Within each survey area, successive crossings were spaced at about 10 km, which should result in complete backscatter and bathymetry coverage of the ridge top, the location of the proposed drilling sites. The proposed drill sites, enumerated LORI 1-7, were selected on the basis of single chirp profiler records collected from the icebreaker Oden and single seismic reflection profiles collect from the icebreaker Polarstern. Dense SCAMP data was collected near the northernmost LORI sites (1-3) and the LORI-5 site. The submarine sailed directly over the LORI-4 site in transit between the southern and central survey areas. The remaining sites (LORI-6 and 7) were not visited during this cruise. The proposed ODP drilling has adopted an offset drilling strategy along the eroded upper flanks of the Lomonosov Ridge in order to sample the entire 500 m thick post-Paleocene sediment sequence in 100-200 m thick increments. The SCAMP data is crucial for optimizing the site selection.
Myers, G., D. Chayes, et al. (1998). "Seanet: Ship/Shore Communications: High-speed Ship-to-Shore Transmission of Wireline Loging Data." Sea Technology 39(6): 80-82.
Chayes, D., B. Coakley, et al. (1998). Enhanced Geophysical Instrumenation for SCICEX: the Seafloor Characterization and Mapping Pods (SCAMP). The Arctic Forum, Washington DC, Arctic Research Consortium of the US.
Chayes, D., G. Kurras, et al. (1998). Swath Mapping the Arctic Ocean from US Navy Submarines; Installation and Performance Analysis of SCAMP Operation During SCICEX 1998. 1998 AGU Fall meeting, San Francisco, CA, AGU.
It has been widely recognized that the stability, silence, range and independence from surface conditions render a nuclear-powered submarine a nearly ideal platform for geophysical data acquisition. The submarine's independence from surface conditions is a particular advantage in the Arctic. The SCICEX program, in which the Navy provides Arctic submarine services to conduct civilian science projects, has made possible the first ever systematic bathymetric surveys in the Arctic basin.
In recognition of this unique opportunity, NSF's Office of Polar Programs funded the fabrication, testing, installation and operation of a SeaMARC-type sidescan swath bathymetric sonar and a data acquisition and quality control system. In support of NSF's commitment, a private organization, the Palisades Geophysical Institute, funded acquisition of a chirp, swept-frequency sub-bottom profiler.
The ODEC sub-bottom profiler and Raytheon sidescan swath bathymetric system were delivered in early 1998. The transducer pods, which had been designed by the Applied Physics Lab (APL) of Johns Hopkins University, and Electric Boat Company, were fabricated in machine shops at APL and Twin Manufacturing. The data acquisition system had been developed by LDEO and tested earlier on the 1997 SCICEX cruise of USS Archerfish.
SCAMP is one of the most complicated civilian instruments ever installed on a U.S. Navy submarine. This installation required the coordinated efforts of personnel from LDEO, APL, Electric Boat, and
Norfolk Naval Shipyard; as well as the unfailing cooperation of the Navy personnel of USS Hawkbill, Submarine Squadron One, and COMSUBPAC. Installation was accomplished in two phases: Hard mounting points were welded to the submarine hull during a drydock period in July 1997; in May 1998 the massive transducer pods were installed dockside by divers, using purpose-built handling gear and
crane support. Inboard electronics were installed with the rest of the SCICEX science equipment in May 1998. The combined sonar systems were tested in May and June during shakedown cruises. Some problems with the swath system were identified and corrected during port stops prior to arrival of USS Hawkbill in the Arctic Ocean.
While the geophysical objectives of the cruise were focused on the ultra-slow spreading Gakkel Ridge, where more than 3300 km of track data were collected over the ridge axis, underway data was collected during all phases of the program, across the Chukchi Plateau, the Alpha Ridge and the Lomonosov Ridge. The data collected during SCICEX 98 provide the first detailed characterization of these features. Samples of the data collected over these features as well as documentation of the installation process will be shown in this poster.
Chayes, D., G. Myers, et al. (1998). "Seanet: Ship/Shore Communications: Extending the Internet to the Oceanographic Research Fleet." Sea Technology 39(5): 17-21.
Pyle, T. E., M. Ledbetter, et al. (1997). "Arctic Ocean Science." Sea Technology 38 No. 10(October 1997): 10-15.
Chayes, D., A. Maffei, et al. (1997). SeaNet Lite: On Demand Internet Connectivity at Sea. OCEANS '97, IEEE.
Chayes, D. N., B. J. Coakley, et al. (1997). SCAMP: A submarine-mounted geophysical survey system for use under the Arctic ice. Oceans' 97, Halifax, NS, IEEE.
US Navy nuclear submarines are being used for unclassified scientific missions in the Arctic under the terms of a memorandum of agreement between the Navy, the Office of Naval Research, the National Science Foundation (NSF), the U.S. Geological Survey and the National Oceanic and Atmospheric Administration. Thus far, the tools for geophysical survey have been limited to a BGM-3 gravity meter and a 12 kiloHertz single beam echo sounder. With support from the National Science Foundation, the Palisades Geophysical Institute, and Columbia University, we have completed the design of and are in the process of building and testing the Seafloor Characterization and Mapping Pod (SCAMP) which consists of a Sidescan Swath Bathymetric Sonar (SSBS), a High Resolution Subbottom Profiler (HRSP) and integrated with a physically compact Data Acquisition and Quality Control System (DAQCS.)
Shallow towed SSBS designs are readily adapted for the unique requirements of this program A 12 kiloHertz SeaMARC design has been adapted for under-ice use. In addition to the physical installation requirements (including the requirement to move from boat to boat) for the submarine mounted application, significant effort has been made in the transducer array design to minimize the influence of the ice canopy and pressure ridges on the sidescan and bathymetric data. The arrays have four rows of elements with beam steering on transmit and receive. Anticipated performance of the SSBS includes swath imagery over a 150 degree swath with good bathymetry over at least 130 degrees in water depths of 2 to 3 km.. The along track beam width will be 1.2 degrees with an asymmetrical 30 degree vertical beam width.
A Bathy-2000P FM modulated subbottom profiler is also being adapted for this system. An array of 16 DT-109 transducers driven by the integral 2 kilowatts transmitter will produce a beam pattern of 24 degrees. Seafloor penetration of up 100 meters with a resolution on the order of 30 cm is anticipated.
Transducer arrays for each of the sonar systems will be mounted in independent pods under the keel without significantly increasing the draft or modifying the operational envelope of the boat. A significant portion of the electronics for the SSBS will be mounted outboard under the foredeck with the remainder inboard. The required electrical hull penetrators will be accommodated through existing hull fittings.
The system will be tested in a towed configuration in Puget Sound in the spring of 1997 as part of the acceptance trials. Deployment of this system to the Arctic is targeted for the SCICEX cruise in the summer of 1998 after installation on the submarine and one or more shakedown cruises.
Chayes, D. N., B. J. Coakley, et al. (1996). SCAMP: An Enhanced Geophysical Mapping System for Arctic Submarine Cruises. 1996 AGU Fall meeting, San Francisco, AGU.
Implementation is currently underway for
a significant enhancement to the
geophysical survey capability for use in
the SCICEX program of unclassified
science cruises on US Navy
nuclear-powered attack submarines in the
Arctic. Under an existing memorandum of
understanding between the Navy, ONR, NSF,
NOAA and USGS, nuclear submarines will be
used on unclassified research cruises to
the high arctic in 1997, 1998, and
1999. Previous cruises under this program
have collected single beam bathymetry and
gravity anomaly data in addition to making
physical, chemical and biological
measurements.
L-DEO is working with Alliant
Techsystems, the Navy's Arctic Submarine
Lab and the Hawaii Mapping Research Group
to design, fabricate, and install an
integrated geophysical instrument package
for future submarine cruises to the
Arctic. For the 1997 cruise, we will add
a SeaMARC sidescan swath bathymetry
system and a swept frequency subbottom
profiler along with a significantly
improved data acquisition and quality
control data system.
With the new system, we believe it will
be possible to collect on the order of
one million square kilometers of combined
backscatter and bathymetric data with
high quality subbottom and gravity
anomaly data along about 60,000
kilometers of track during the remaining
three years of this program. This data will
revolutionize our understanding of the
Arctic seafloor and the continents that
ring the Arctic. Implementation
schedule, block diagrams, data flow
diagrams, and anticipated performance
specifications of the new system will be
presented.
Caress, D. W. and D. N. Chayes (1996). "Improved Processing of Hydrosweep Multibeam Data on the R/V Maurice Ewing." Marine Geophysical Researches 18: 631-650.
Maffei, A. R., E. S. Kappel, et al. (1995). SeaNet Collaboratory: Building an Internet
for Remote Research. 1995 AGU Fall meeting, San Francisco, CA, AGU.
The SeaNet collaboratory encourages the integration of
existing and future ocean located computers and data
communications technologies into a well connected mesh. It
looks towards more transparent inter-connectivity between
computing devices at sea (and other remote research sites).
Instead of developing new communications technologies
itself, the project identifies and promotes the use of
current and future technologies that have already proven
reliable enough for integration into an at-sea
internetwork. It then helps to integrate these into an
ocean based internetwork of manned and unmanned research
platforms to be connected into the existing Internet.
Such integration can be encouraged by first developing a
model of what the ocean portion of the Internet might look
like and then demonstrating the capabilities of selected
components required to implement such a model. Two such
components: 1) a 64kbit/s synchronous, INMARSAT-B, TCP/IP
channel and 2) a Shipboard Communications Node (SCN), are
described.
Caress, D. W. and D. N. Chayes (1995). New Software for Processing Sidescan Data from Sidescan-Capable Multibeam Sonars. IEEE Oceans '95, San Diego, CA., IEEE.
We have developed new softwaer tools for the processing and display of sidescan data optained with the latest generation of multibeam sonars; the programs are distributed as part of the MB-System softwarwe packages. The new utilities provide a straightforward means for several common processing tasks, including analyzing the drop in backscatter intensity with increasing grazing angle, correcting sidescan images for the amplitude vs. grazing angle variation, and filtering. The grazing angle correction is particularly effective when applied to multibeam sonar sidescan for which high resolution co-registerd bathymetry is available. Examples are prvided using multibeam sidescan and bathymetry obtained using a 12 kHz, 120 degree SeaBeam 2112 sonar.
Purdy, G. M., B.B. Walden, et al. (1994). Tests of the SeaBeam 2100/12 Multibeam System. Woods Hole, MA, Woods Hole Oceanographic Institution.
Chayes, D. N. and P. Lemmond (1994). First Results from a new generation of Multibeam Sonars, Abstract XXXX-XX. 1994 AGU Fall meeting, San Francisco, CA, AGU.
The first full installation of a SeaBeam 2112 was made on the
R/V KNORR in August, 1994. The transducers for a SB2112 were installed
on the R/V PALMER in June 1994 and the electronics will be installed in
September.
Initial testing on the Knorr occured during a transit from
Woods Hole to Scicily. Further testing will take place during a transit
from Scicily to Freemantle Austraila. Initial results indicate a swath
width of 8500 meters in 2800 meters of water. The SB2112 collects
simultaneous bathymetry and co-located, geometrically corrected
sidescan-sonar data.
Sea trials for the system on the PALMER are scheduled for
October 14 and for the KNORR in November. Results from the initial
testing and from the sea trials will be presented.
Barstow, N., K. Jacob, et al. (1994). Lamont's LDEO/NCEER Strong-Motion Database: What's in It and How to Use It. 1994 AGU Fall meeting, San Francisco, AGU.
Chayes, D. N. and D. W. Caress, Chayes, D.N (1993). Processing and Display of Multibeam Echosounder Data on the R/V Maurice Ewing. Fall Meeting, San Francisco, CA, AGU.
Chayes, D. N. (1991). Hydrosweep-DS on the R/V Ewing. OCEANS 1991, Honolulu, IEEE.
Stoll, R. D., G. M. Bryan, R. Flood, D. Chayes, and P. Manley (1988). "Shallow seismic experiments using shear waves." J. Accoust. Soc. Am 83(1): 93-102.
Shor, A. and C. D. (1986). Navitagion for Surveys of Trans-Pacific Fiber-Optic Cables. International Symposium on Marine Positioning, Reston VA, D. Reidel.
Chayes, D., H. Chezar, et al. (1984). New Application for Ocean Bottom Survey Using Submersibles and Towed Sleds. Underwater Photography, Scientifc and Engineering Applications. P. F. Smith. North Falmouth, Massachusetts, Benthos, Inc.: 121-126.
Kosalos, J. G. and D. N. Chayes (1983). A portable system for ocean bottom imaging and charting. Oceans ’83, Los Angeles, CA, IEEE.
Chayes, D. N. (1983). Evolution of Sea MARC I. Third Workding Symposium on Oceanographich DAta Systems, Woods Hole, MA, IEEE Computer Society.
Chayes, D. N. and M. Erickson (1973). "Preliminary Paleocurrent Analysis from Cross-Strata in the Timber Lake Member, Fox Hills Formation, In North Dakota." The Compass 50(2): 38-44.