Multibeam echo sounder - GeoTIFF grids for processed Reson 7160 seafloor bathymetry data collected during USGS field activities 2017-001-FA and 2017-002-FA.

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Frequently anticipated questions:

What does this data set describe?

Title:
Multibeam echo sounder - GeoTIFF grids for processed Reson 7160 seafloor bathymetry data collected during USGS field activities 2017-001-FA and 2017-002-FA.
Abstract:
In spring and summer 2017, the U.S. Geological Survey’s Gas Hydrates Project conducted two cruises aboard the research vessel Hugh R. Sharp to explore the geology, chemistry, ecology, physics, and oceanography of sea-floor methane seeps and water column gas plumes on the northern U.S. Atlantic margin between the Baltimore and Keller Canyons. Split-beam and multibeam echo sounders and a chirp subbottom profiler were deployed during the cruises to map water column backscatter, sea-floor bathymetry and backscatter, and subsurface stratigraphy associated with known and undiscovered sea-floor methane seeps. The first cruise, known as the Interagency Mission for Methane Research on Seafloor Seeps and designated as field activity 2017-001-FA, was conducted from May 4 to May 11, 2017, and acquired geophysical data to support remotely operated vehicle exploration of seep sites using the Global Explorer, which is operated by Oceaneering International, Inc. Geophysical operations during cruise 2017-002-FA from August 25 to September 6, 2017, were also focused on mapping water column methane plumes, sea-floor seep sites, and subseafloor strata, but primarily supported conductivity, temperature, and depth instrument deployment, surface-water methane-concentration mapping, and water-sampling operations as part of a collaborative study with the University of Rochester of the effect of methane seepage on ocean water biogeochemistry. The National Oceanic and Atmospheric Administration’s Office of Ocean Exploration and Research partially sponsored cruise 2017-001-FA, and the U.S. Department of Energy partially sponsored both cruises.
Supplemental_Information:
Support for 2017-001-FA was provided to the USGS by NOAA and DOE through interagency agreements 16-01118 and DE-FE0023495, respectively. Support for 2017-002-FA was provided to the USGS and the University of Rochester by DOE through interagency agreement DE-FE0026195 and grant DE-FE0028980, respectively. Additional information on the field activities are available from https://cmgds.marine.usgs.gov/fan_info.php?fan=2017-001-FA and https://cmgds.marine.usgs.gov/fan_info.php?fan=2017-002-FA. Additional information specific to the Interagency Mission for Methane Research on Seafloor Seeps is available at https://www.usgs.gov/centers/whcmsc/science/immerss-interagency-mission-methane-research-seafloor-seeps?qt-science_center_objects=0#qt-science_center_objects and https://archive.usgs.gov/archive/sites/soundwaves.usgs.gov/2017/05/outreach.html.
  1. How might this data set be cited?
    U.S. Geological Survey, 20200409, Multibeam echo sounder - GeoTIFF grids for processed Reson 7160 seafloor bathymetry data collected during USGS field activities 2017-001-FA and 2017-002-FA.: data release DOI:10.5066/P9Y1MSTN, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, Massachusetts.

    Online Links:

    This is part of the following larger work.

    Baldwin, Wayne E., Moore, Eric M., Worley, Charles R., Nichols, Alex R., and Ruppel, Carolyn D., 2020, Marine Geophysical Data Collected to Support Methane Seep Research Along the U.S. Atlantic Continental Shelf Break and Upper Continental Slope Between the Baltimore and Keller Canyons During U.S. Geological Survey Field Activities 2017-001-FA and 2017-002-FA.: data release DOI:10.5066/P9Y1MSTN, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Suggested citation: Baldwin, W.E., Moore, E.M., Worley, C.R., Nichols, A.R., and Ruppel, C.D., 2020, Marine Geophysical Data Collected to Support Methane Seep Research Along the U.S. Atlantic Continental Shelf Break and Upper Continental Slope Between the Baltimore and Keller Canyons During U.S. Geological Survey Field Activities 2017-001-FA and 2017-002-FA: U.S. Geological Survey data release, https://doi.org/10.5066/P9Y1MSTN.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -74.873341
    East_Bounding_Coordinate: -74.009451
    North_Bounding_Coordinate: 37.859121
    South_Bounding_Coordinate: 35.497230
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/5e7d1495e4b01d5092751d95/?name=2017-001-FA_2017-002-FA_7160Bathymetry_browse.jpg (JPG)
    Example MBES bathymetry imagery from around Keller Canyon.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 09-May-2017
    Ending_Date: 06-Sep-2017
    Currentness_Reference:
    ground condition
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: raster digital data
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 18N
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.9996
      Longitude_of_Central_Meridian: -75
      Latitude_of_Projection_Origin: 0
      False_Easting: 500000
      False_Northing: 0
      Planar coordinates are encoded using row and column
      Abscissae (x-coordinates) are specified to the nearest 25
      Ordinates (y-coordinates) are specified to the nearest 25
      Planar coordinates are specified in meters
      The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: instantaneous sea level
      Depth_Resolution: 0.1
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    2017-001-FA_2017-002-FA_7160Bathymetry_BetweenWashingtonAndAccomacCanyons_25m.tiff
    32-Bit floating-point GeoTIFF image of processed Reson 7160 MBES bathymetry collected between Washington and Accomac Canyons during USGS field activities 2017-001-FA and 2017-002-FA. (Source: U.S. Geological Survey)
    2017-002-FA_7160Bathymetry_AroundNorfolkCanyon_25m.tiff
    32-Bit floating-point GeoTIFF image of processed Reson 7160 MBES bathymetry collected around Norfolk Canyon during USGS field activity 2017-002-FA. (Source: U.S. Geological Survey)
    2017-002-FA_7160Bathymetry_AroundKellerCanyon_25m.tiff
    32-Bit floating-point GeoTIFF image of processed Reson 7160 MBES bathymetry collected around Keller Canyon during USGS field activity 2017-002-FA. (Source: U.S. Geological Survey)
    Entity_and_Attribute_Overview:
    Bathymetric values in the 32-bit GeoTIFF grids are in meters relative to instantaneous sea level. '2017-001-FA_2017-002-FA_7160Bathymetry_BetweenWashingtonAndAccomacCanyons_25m.tiff' consists of 1175 columns and 1583 rows, and has minimum and maximum elevations of -1227 and -152.5 meters, respectively. '2017-002-FA_7160Bathymetry_AroundNorfolkCanyon_25m.tiff' consists of 686 columns and 1627 rows, and has minimum and maximum elevations of -680.8 and -89.4 meters, respectively. '2017-002-FA_7160Bathymetry_AroundKellerCanyon_25m.tiff' consists of 407 columns and 1131 rows, and has minimum and maximum elevations of -1019.9 and -49.1 meters, respectively.
    Entity_and_Attribute_Detail_Citation: U.S. Geological Survey

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • U.S. Geological Survey
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
    U.S. Geological Survey
    Attn: Wayne E. Baldwin
    Geologist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    US

    508-548-8700 x2226 (voice)
    508-457-2310 (FAX)
    wbaldwin@usgs.gov

Why was the data set created?

These GeoTIFF grids represent the processed Reson 7160 multibeam echo sounder seafloor bathymetry data collected by the U.S. Geological Survey during USGS field activities 2017-001-FA and 2017-002-FA along the U.S. Atlantic continental shelf break and upper slope between Accomac and Keller Canyons. The data depict seafloor bathymetry associated with shelf-edge, submarine canyon, and upper slope environments in which seafloor methane seeps have been identified. The data are intended to be used in conjunction with other geophysical, ROV dive imagery, and geologic sample data to investigate sea-floor morphology and geologic framework associated with sites of methane seepage.

How was the data set created?

  1. From what previous works were the data drawn?
    Reson 7160 multibeam echo sounder data (source 1 of 1)
    U.S. Geological Survey, Unpublished Material, raw MBES data in s7k and HSX formats.

    Type_of_Source_Media: disc
    Source_Contribution:
    Multibeam echo sounder seafloor bathymetry and backscatter and water column backscatter data were collected using a Reson 7160 (44 kHz center frequency, 512 beams, 1.5 x 2 degree across- and along-track beam widths, respectively). The Mills Cross transmit and receive transducer arrays were pole-mounted on the port side of the R/V Hugh R Sharp just aft of the Bosun's locker with the transducers positioned approximately 2.8 m below the waterline when deployed. Vessel navigation and attitude data were acquired with an Applanix POS MV Wavemaster (model 220, v5) configured with two Trimble GPS antennas located at either end of a 2-m baseline oriented fore and aft and mounted atop the MBES pole, and the wet pod IMU mounted atop the sonar bracket just aft of the pole. An AML Micro X SV mounted on the sonar bracket monitored sound speed in water near the sonar during acquisition, and water column sound speed profiles were collected using Sippican T4 and T5 Expendable Bathythermograph probes and Seabird Electronics 911plus CTD casts at various points during both cruises (see shapefile '2017-001-FA_2017-002-FA_SVPdata.shp' available from the larger work citation). The Reson SeaBat User Interface (version 4.0.0.10) was used to control the sonar, which was operated primarily in FM mode at various power levels throughout the cruises. The range of the 512 across-track beams formed by the sonars were adjusted manually depending on water depth. Data were monitored and recorded using the Reson SeaBat User Interface (version 4.0.0.10) and HYPACK HYSWEEP (version 2017, 17.1.3.0). The SeaBat User Interface logged navigation, attitude, bathymetry, time-series backscatter, and water column data to s7k format files. HYPACK HYSWEEP logged navigation, attitude, and bathymetry data to HSX format files, and navigation, attitude, and time series backscatter data to 7K format files. Patch test calibrations were performed during each field activity to determine possible misalignments between the MBES and POS MV reference frames or systematic timing latencies.
  2. How were the data generated, processed, and modified?
    Date: 2017 (process 1 of 3)
    Shipboard multibeam bathymetry processing within Caris HIPS (version 9) consisted of the following flow:
    1) Caris HIPS projects were created to process 7160 data. Projection information was set to Universal Transverse Mercator (UTM) Zone 18N, WGS 84.
    2) Vessel configuration files were created in the Caris projects for the R/V Hugh R. Sharp, which included relevant linear and angular installation offsets for the 7160 installation as well as vendor specified uncertainty values for each of the survey sensors.
    3) Raw files were imported to the Caris projects using the Import/Conversion Wizard.
    4) Delayed heave and navigation data (navigation only loaded for HSX data used from JD238 of 2017-002-FA) from raw POS MV files were used to update HIPS survey lines using the import auxiliary data function.
    5) Navigation was reviewed and edited as needed using the Navigation Editor tool.
    6) Sound velocity correction was applied using the Caris algorithm, a master SVP file containing all the sound velocity profiles collected during the cruise and specifying the nearest in distance method, delayed heave source, and use surface sound speed.
    7) Data were merged selecting no tide and the delayed heave source.
    8) 25-m resolution swath-angle surfaces were created to incorporate files for each area as they were processed, and data were reviewed for inconsistencies and anomalies. Shipboard processing was primarily focused on QA/QC during acquisition.
    This process step and all subsequent process steps were conducted by Eric Moore and Wayne Baldwin, though Baldwin is listed as the contact. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Wayne Baldwin
    Geologist
    384 Woods Hole Rd.
    Woods Hole, MA

    508-548-8700 x2226 (voice)
    508-457-2310 (FAX)
    wbaldwin@usgs.gov
    Date: Oct-2019 (process 2 of 3)
    Post-cruise multibeam bathymetry processing within Caris HIPS (version 10.4) consisted of the following flow:
    1) The swath and subset editors were used to remove spurious points through manual editing and filter application, and the refraction editor was used to adjust sound speed values in areas where sound velocity data did not adequately correct depth profiles obviously influenced by local anomalies in speed of sound through the water column.
    2) Survey lines adjusted for refraction anomalies were remerged, and the respective surfaces were recomputed to reflect the changes. Editing processes required trial and error, and were at times iterative.
    3) The final edited swath angle surfaces were exported from HIPS as 25-m per pixel 32-Bit floating-point GeoTIFF files (UTM Zone 18N, WGS 84)
    Date: 06-Aug-2020 (process 3 of 3)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?
    Demopoulos, A., McClain-Counts, J., Bourque, J., Prouty, N., Smith, B., Brooke, S., Ross, S., and Ruppel, C., 2019, Examination of Bathymodiolus childressi nutritional sources, isotopic niches, and food-web linkages at two seeps in the US Atlantic margin using stable isotope analysis and mixing models.: Deep Sea Research Part I 148, pp.53-66, Elsevier, Amsterdam, Netherlands.

    Online Links:

    Leonte, M., Ruppel, C. D., Ruiz‐Angulo, A., and Kessler, J. D., 2020, Surface methane concentrations along the Mid‐Atlantic Bight driven by aerobic subsurface production rather than seafloor gas seeps.: Journal of Geophysical Research: Oceans vol. 125, American Geophysical Union Publications, Washington, DC.

    Online Links:

    Ruppel, C., Demopoulos, A., and Prouty, N., 2018, Exploring US Mid-Atlantic Margin Methane Seeps: IMMeRSS, May 2017.: Supplement to Oceanography 31(1), p.93, The Oceanography Society, Rockville, MD.

    Online Links:

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
    Navigation data were acquired using the WGS 84 coordinate system with an Applanix POS MV Wavemaster (model 220, v5), which blends Global Navigation Satellite System (GNSS) and acceleration data from an Inertial Motion Unit (IMU) and GPS azimuthal heading. The POS MV was configured with two Trimble GPS antennas located at either end of a 2-m baseline, which was oriented fore and aft and mounted atop the MBES pole just aft of the bosun's locker on the port side of vessel. GPS positions were obtained from the primary antenna located on the forward end of the baseline, and the positional offsets between the antenna and the navigational reference point (the POS MV IMU) were accounted for in the Applanix POSView (version 8.60) acquisition software. Positions from the POS MV are assumed to be horizontally accurate to 3 meters.
  3. How accurate are the heights or depths?
    On the basis of overlap comparison with existing MBES coverage in the study area, we conservatively estimate that vertical accuracy of the processed data are within approximately 1 percent of water depth (4.9 to 12.7 m within the area covered by these grids). The Applanix Wavemaster POS MV Attitude and Positioning system, used to correct for vessel roll, pitch, heave, and yaw, has a theoretical vertical accuracy of a few mm and thus aids in removing spurious artifacts that may be caused by motion. Processed soundings are referenced to instantaneous sea level and no tidal corrections have been applied. Sound speed profiles (see shapefile '2017-001-FA_2017-002-FA_SVPdata.shp' available from the larger work citation) collected using Sippican T4 and T5 Expendable Bathythermograph probes and Seabird Electronics 911plus CTD casts were used during post-processing to minimize acoustic refraction artifacts in the bathymetry data. Changes in ship draft due to water and fuel usage were not considered.
  4. Where are the gaps in the data? What is missing?
    Most of the MBES bathymetry collected along tracklines included in '2017-001-FA_2017-002-FA_7160Tracklines' were used to produce these raster grids. The sole exceptions were exclusion of data from HSX files 20170826_010146_000_0101, 20170826_010810_000_0108, 20170826_010928_000_0109, 20170826_014853_000_0148, 20170826_022534_000_0225, 20170826_025823_000_0258, and 20170826_034104_000_0341 and the s7k file 20170827_081525 from '2017-001-FA_2017-002-FA_7160Bathymetry_BetweenWashingtonAndAccomacCanyons_25m.tiff'.
  5. How consistent are the relationships among the observations, including topology?
    These GeoTIFF rasters represent processed Reson 7160 multibeam echo sounder (MBES) seafloor bathymetry data gridded at a 25-m resolution. Quality control and data processing were conducted to remove spurious points and reduce sound speed artifacts (refraction) using Computer Aided Resource Information System (Caris) Hydrographic Information Processing System (HIPS; versions 9 and 10.4). While the navigation and attitude data in the bathymetry data and accompanying backscatter data available from the larger work citation (https://www.sciencebase.gov/catalog/item/5e179176e4b0ecf25c59f97a) are identical, the extents of the processed bathymetry grids and backscatter mosaics differ slightly due to differences in processing.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: none
Use_Constraints:
These data are not to be used for navigation. Mariners should refer to the appropriate nautical chart. Public domain data from the U.S. Government are freely distributable with proper metadata and source attribution. Please recognize the U.S. Geological Survey as the originator of the data set.
  1. Who distributes the data set? (Distributor 1 of 1)
    U.S. Geological Survey - ScienceBase
    Federal Center
    Denver, CO

    1-888-275-8747 (voice)
  2. What's the catalog number I need to order this data set? USGS data release of processed Reson 7160 MBES seafloor bathymetry grids collected along the U.S. Atlantic continental shelf break and upper slope between Accomac and Keller Canyons during USGS field activities 2017-001-FA and 2017-002-FA: includes the 32-Bit floating-point GeoTIFF images '2017-001-FA_2017-002-FA_7160Bathymetry_BetweenWashingtonAndAccomacCanyons_25m.tiff', '2017-002-FA_7160Bathymetry_AroundNorfolkCanyon_25m.tiff', and '2017-002-FA_7160Bathymetry_AroundKellerCanyon_25m.tiff', the browse graphic '2017-001-FA_2017-002-FA_7160Bathymetry_browse.jpg', and the Federal Geographic Data Committee (FGDC) Content Standards for Digital Geospatial Metadata (CSDGM) metadata file 2017-001-FA_2017-002-FA_7160Bathymetry_meta.xml.
  3. What legal disclaimers am I supposed to read?
    Neither the U.S. Government, the Department of the Interior, nor the USGS, nor any of their employees, contractors, or subcontractors, make any warranty, express or implied, nor assume any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, nor represent that its use would not infringe on privately owned rights. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the USGS in the use of these data or related materials. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  4. How can I download or order the data?
  5. What hardware or software do I need in order to use the data set?
    To utilize these data, the user must have geographic information system or similar software capable of displaying 32-bit GeoTIFF grid files.

Who wrote the metadata?

Dates:
Last modified: 06-Aug-2020
Metadata author:
U.S. Geological Survey
Attn: Wayne E. Baldwin
Geologist
384 Woods Hole Rd.
Woods Hole, MA

(508) 548-8700 x2226 (voice)
(508) 457-2310 (FAX)
wbaldwin@usgs.gov
Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata (FGDC-STD-001-1998)
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