Sea floor topography and backscatter intensity of the historic area remediation site

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Metadata:

Identification_Information:
Citation:
Citation_Information:
Originator: U.S. Geological Survey
Publication_Date: 2003
Title:
Sea floor topography and backscatter intensity of the historic area remediation site
Geospatial_Data_Presentation_Form: remote-sensing image and raster digital data
Series_Information:
Series_Name: U.S. Geological Survey Open-File Report
Issue_Identification: 01-470
Publication_Information:
Publication_Place: Woods Hole, MA
Publisher: U.S. Geological Survey
Online_Linkage: http://pubs.usgs.gov/of/2001/of01-470/
Larger_Work_Citation:
Citation_Information:
Originator: Butman, Bradford
Originator: Gutierrez, Benjamin T.
Originator: ten Brink, Marilyn Buchholtz
Originator: Schwab, William C.
Originator: Blackwood, Dann S.
Originator: Mecray, Ellen L.
Originator: Middleton, Tammie J.
Publication_Date: 2003
Title:
Photographs of the sea floor offshore of New York and New Jersey
Geospatial_Data_Presentation_Form:
map, raster digital data, remote-sensing image, tabular digital data, vector digital data
Series_Information:
Series_Name: U.S. Geological Survey Open-File Report
Issue_Identification: 01-470
Publication_Information:
Publication_Place: Woods Hole, MA
Publisher: U.S. Geological Survey
Online_Linkage: http://pubs.usgs.gov/of/2001/of01-470/
Description:
Abstract:
This data set includes topography and backscatter intensity of the sea floor of the Historic Area Remediation Site (HARS), located offshore of New York and New Jersey. The data were collected with a multibeam sea floor mapping system on surveys conducted November 23 - December 3, 1996, October 26 - November 11, 1998, and April 6 - 30, 2000. The surveys were conducted using a Simrad EM 1000 multibeam echo sounder mounted aboard the Canadian Hydrographic Service vessel Frederick G. Creed. This multibeam system utilizes 60 electronically aimed receive beams spaced at intervals of 2.5 degrees that insonify a strip of sea floor up to 7.5 times the water depth (swath width of 100 to 200 m within the survey area). The horizontal resolution of the beam on the sea floor is approximately 10% of the water depth (3-5 meters in the survey region). Vertical resolution is approximately 1 percent of the water depth, or 0.3 m. Maps derived from the mulitbeam observations show sea floor topography, shaded relief, and backscatter intensity (a measure of sea floor texture and roughness) at a spatial resolution of 3 m/pixel. These data have been reprocessed from those presented in Butman and others (2002) (see cross reference) to correct for an error in the software that projected the data on a sphere rather than on the WGS84 ellipsoid, and to stretch the backscatter intensity and shaded relief images to match the Hudson Shelf Valley images. The horizontal error in placement of the data published by Butman and others (2002) was 0 in the northwestern corner of the HARS, and reached about 12 m in the southeastern corner. Further work is needed to match the backscatter intensity for the 1996, 1998, and 2000 surveys.
Purpose:
These data are included in this publication to provide bathymetry and backscatter intensity of the sea floor for maps showing the locations of images and samples obtained in the New York Bight.
Data_Set_Structure:
Data_Set_Part:
Part_Type: remote-sensing images
Part_Name: Sun illuminated topography
Part_Description: The shaded relief image (3 m pixel size) was created by vertically exaggerating the topography four times and then artificially illuminating the relief by a light source positioned 45 degrees above the horizon from the north. In the resulting image, topographic features are enhanced by strong illumination on the northward-facing slopes and by shadows cast on southern slopes. The image also accentuates small features (relief of a few meters) that could not be effectively shown as contours alone at this scale. Unnatural-looking features or patterns oriented parallel or perpendicular to survey tracklines (tracklines run north-south) are artifacts of data collection and environmental conditions.
Data_Set_Part:
Part_Type: remote-sensing image
Part_Name: har96sun.tif
Part_Description: This is a 3 meter resolution tiff image representing sea floor topography with an artificial illumination source. It was compiled from multibeam echosounder data collected in 1996. There is a corresponding tiff world file (.tfw) for georeferencing purposes.
Data_Set_Part:
Part_Type: remote-sensing image
Part_Name: har98sun.tif
Part_Description: This is a 3 meter resolution tiff image representing sea floor topography with an artificial illumination source. It was compiled from multibeam echosounder data collected in 1998. There is a corresponding tiff world file (.tfw) for georeferencing purposes.
Data_Set_Part:
Part_Type: remote-sensing image
Part_Name: har00sun.tif
Part_Description: This is a 3 meter resolution tiff image representing sea floor topography with an artificial illumination source. It was compiled from multibeam echosounder data collected in 2000. There is a corresponding tiff world file (.tfw) for georeferencing purposes.
Data_Set_Part:
Part_Type: remote-sensing images and raster digital data
Part_Name: Backscatter Intensity
Part_Description: Backscatter intensity, the intensity of the acoustic return from the sea floor from the multibeam system, is a function of the properties of the surficial sediments and of the bottom roughness. Generally, a strong return (light gray tones) is associated with rock or coarse-grained sediment, and a weak return (dark gray tones) with fine-grained sediments. However, the micro-topography, such as ripples, burrows, and benthic populations also affect the reflectivity of the sea floor. Direct observations, using bottom photography or video, and surface samples, are needed to verify interpretations of the backscatter intensity data. The backscatter data have a weak striping that runs parallel to the shipÂ’s track. Some of the striping is the result of poor data return at nadir that appears as evenly-spaced thin speckled lines. Some striping is also due to critical angle effects, where the intensity of return varies as a function of the angle of incidence of the incoming sound on the sea floor (Hughes-Clark and others, 1997).
Data_Set_Part:
Part_Type: remote-sensing image
Part_Name: har96mos.tif
Part_Description: This is a 3 meter resolution tiff image representing backscatter intensity. It was compiled from multibeam echosounder data collected in 1996. There is a corresponding tiff world file (.tfw) for georeferencing purposes.
Data_Set_Part:
Part_Type: remote-sensing image
Part_Name: har98mos.tif
Part_Description: This is a 3 meter resolution tiff image representing backscatter intensity. It was compiled from multibeam echosounder data collected in 1998. There is a corresponding tiff world file (.tfw) for georeferencing purposes.
Data_Set_Part:
Part_Type: remote-sensing image
Part_Name: har00mos.tif
Part_Description: This is a 3 meter resolution tiff image representing backscatter intensity. It was compiled from multibeam echosounder data collected in 2000. There is a corresponding tiff world file (.tfw) for georeferencing purposes.
Data_Set_Part:
Part_Type: remote-sensing image
Part_Name: Pseudocolored Backscatter Intensity
Part_Description: The backscatter intensity is combined with the topography to display the distribution of intensity in relation to the topography. In the image shown here, the backscatter intensity is represented by a suite of eight colors ranging from blue, which represents low intensity, to red, which represents high intensity. These data are draped over a shaded relief image created by vertically exaggerating the topography four times and then artificially illuminating the relief by a light source positioned 45 degrees above the horizon from an azimuth of 350 degrees. The resulting image displays light and dark intensities within each color band that result from a feature's position with respect to the light source. For example, north-facing slopes, receiving strong illumination, show as a light intensity within a color band, whereas south-facing slopes, being in shadow, show as a dark intensity within a color band.
Data_Set_Part:
Part_Type: remote-sensing image
Part_Name: har96psu.tif
Part_Description: This is a 3 meter resolution tiff image representing backscatter intensity with a RGB color scale. It was compiled from multibeam echosounder data collected in 1996. There is a corresponding tiff world file (.tfw) for georeferencing purposes.
Data_Set_Part:
Part_Type: remote-sensing image
Part_Name: har98psu.tif
Part_Description: This is a 3 meter resolution tiff image representing backscatter intensity with a RGB color scale. It was compiled from multibeam echosounder data collected in 1998. There is a corresponding tiff world file (.tfw) for georeferencing purposes.
Data_Set_Part:
Part_Type: remote-sensing image
Part_Name: har00psu.tif
Part_Description: This is a 3 meter resolution tiff image representing backscatter intensity with a RGB color scale. It was compiled from multibeam echosounder data collected in 2000. There is a corresponding tiff world file (.tfw) for georeferencing purposes.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 1996
Ending_Date: 2000
Currentness_Reference: ground condition
Status:
Progress: Complete
Maintenance_and_Update_Frequency: None planned
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate: -73.900124
East_Bounding_Coordinate: -73.812264
North_Bounding_Coordinate: 40.433605
South_Bounding_Coordinate: 40.349975
Keywords:
Theme:
Theme_Keyword_Thesaurus: USGS Thesaurus
Theme_Keyword: marine geology
Theme_Keyword: marine geophysics
Theme_Keyword: seismic reflection methods
Theme_Keyword: sea-floor characteristics
Theme_Keyword: geospatial datasets
Theme:
Theme_Keyword_Thesaurus: none
Theme_Keyword: Sea floor photographs
Theme_Keyword: Bottom photography
Theme_Keyword: Sea floor video
Theme_Keyword: Sediment texture
Theme_Keyword: Sediment grain size
Theme_Keyword: Seabed Observation and sampling system
Theme_Keyword: SEABOSS
Theme_Keyword: R/V Oceanus
Theme_Keyword: R/V Endeavor
Theme_Keyword: R/V Seaward Explorer
Theme_Keyword: F/V Alpha and Omega
Theme_Keyword: Woods Hole Field Center
Theme_Keyword: WHFC
Theme_Keyword: United States Geological Survey
Theme_Keyword: USGS
Theme_Keyword: Geographic Information Systems
Theme_Keyword: GIS
Theme_Keyword: Simrad Subsea EM1000
Theme_Keyword: Sea Floor Mapping
Theme_Keyword: Multibeam Echo Sounder
Theme_Keyword: Multibeam
Theme_Keyword: Topographic data
Theme_Keyword: Sea floor topography
Theme_Keyword: Bathymetry
Theme_Keyword: Backscatter intensity
Theme_Keyword: Sea floor geology
Theme_Keyword: Surficial geology
Theme_Keyword: Dredged material
Theme_Keyword: Ocean disposal
Theme_Keyword: Contaminated sediments
Place:
Place_Keyword_Thesaurus: none
Place_Keyword: New York
Place_Keyword: New York Harbor
Place_Keyword: NY
Place_Keyword: New Jersey
Place_Keyword: NJ
Place_Keyword: Mud Disposal Site
Place_Keyword: MDS
Place_Keyword: Historic Area Remediation Site
Place_Keyword: HARS
Place_Keyword: Hudson Shelf Valley
Place_Keyword: Hudson Canyon
Place_Keyword: New York Bight
Place_Keyword: New York Bight Apex
Place_Keyword: Mid-Atlantic Bight
Place_Keyword: Exclusive Economic Zone
Place_Keyword: EEZ
Place_Keyword: Atlantic Ocean
Place_Keyword: Ocean
Access_Constraints: None
Use_Constraints: This information is not for navigational purposes.
Point_of_Contact:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: U. S. Geological Survey
Contact_Person: Bradford Butman
Contact_Position: Oceanographer
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Rd
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Country: USA
Contact_Voice_Telephone: 508-548-8700 x2212
Contact_Facsimile_Telephone: 508-457-2309
Contact_Electronic_Mail_Address: bbutman@usgs.gov
Data_Set_Credit:
The multibeam observations in the HARS were originally published in Butman and others (2002), U.S. Geological Survey Open-File Report 00-503 (see cross-reference citation). These data have been reprocessed to correct for an error in the software that projected the data on a sphere rather than on the WGS84 ellipsoid, and to stretch the backscatter intensity and shaded relief images the same as the Hudson Shelf Valley images.
Cross_Reference:
Citation_Information:
Originator: Butman, Bradford
Originator: Danforth, William W.
Originator: Knowles, Stephen C.
Originator: May, Brian
Originator: Serrett, Laurie
Publication_Date: 2002
Title:
Sea floor topography and backscatter intensity of the Historic Area Remediation Site (HARS), offshore of New York, based on multibeam surveys conducted in 1996, 1998, and 2000.
Geospatial_Data_Presentation_Form:
map, raster digital data, remote-sensing image, tabular digital data, vector digital data
Series_Information:
Series_Name: U.S. Geological Survey Open-File Report
Issue_Identification: 00-503
Publication_Information:
Publication_Place: Woods Hole, MA
Publisher: U.S. Geological Survey
Online_Linkage: http://pubs.usgs.gov/of/2000/of00-503/
Data_Quality_Information:
Completeness_Report:
No further processing or modifications will be made to these data.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
These data were navigated with a Differential Global Positioning System (DGPS); they are accurate to +/- 3 meters, horizontally.
Vertical_Positional_Accuracy:
Vertical_Positional_Accuracy_Report:
These data have been corrected for vessel motion (roll, pitch, heave, yaw) and tidal offsets, and referenced to mean lower low water. The theoretical vertical resolution of the Simrad EM-1000 multibeam echosounder is 1 % of water depth; roughly 30 - 50 cm within the study area. However, the working vertical resolution of the system, is roughly +/- 50 cm.
Lineage:
Process_Step:
Process_Description:
(1) Data and acquisition processing at sea. After the echo sounder data were logged onto the hard disk of the Sun workstation, a suite of processing software developed by the Ocean Mapping Group (www.omg.unb.ca/~jhc/SwathEd.html) was used to correct for artifacts and errors that may have been introduced during data collection. This software also enhanced the corrected data by resolving beam pattern and aspect ratio distortions and by imposing a linear contrast stretch before it generated bathymetric and sidescan sonar image mosaicks in a Mercator projection. All data processing described here is initiated using Silicon Graphics workstations as soon as each acquisition file is closed by the Simrad Mermaid workstation (usually at the end of each survey line). Additional processing was done in the lab to correct for fluctuations in sea level during the survey and for artifacts in the data files that were not corrected in the field (see below). The processing and editing steps on board the ship were:
(A.) Demultiplex, or unravel, the acquired Simrad data files using RT to generate separate files containing navigation, depth soundings, sidescan sonar backscatter values, and sound velocity information.
(B.) Automatically reject bad data (autoRejectSoundings). For the multibeam soundings, reject data outside expected depth ranges (operator's decision based on nautical chart data); for navigation data, reject fixes with poor GPS statistics.
(C.) Edit the navigation data on-screen using jview to remove undesirable points, including turns at the ends of survey lines.
(D.) Edit the multibeam soundings on-screen using swathed to remove individual anomalous soundings.
(E). Merge tidal information and the corrected navigation back (mergetide and mergenav) into the data files. Tidal information was obtained from the NOAA tide server using tide station 8531680 located at Sandy Hook, Final tidal corrections were made in the lab using a different procedure (see below).
(F.) Map the bathymetric soundings from each processed data file onto a Mercator grid using weigh_grid with node spacings and scale selected by the operator.
(G.) Map the extracted sidescan sonar backscatter values onto a digital mosaic using mos2 in the Mercator projection at a scale selected by the user.
(H.) Using addSUN, generate bathymetric raster files using the mapped grid node information to depict the depth information in a shaded relief Mercator map. A Mercator projection allows individual map areas to be joined edge to edge when creating a composite image. The shaded relief images were generated using a sun elevation angle of 45 degrees from an azimuth of 0 degrees, and a vertical exaggeration of four times to emphasize sea floor features.
(I.) Generate a false colored image using mix_ci by combining the bathymetric and backscatter raster mosaics into a single image, also in the Mercator projection.
(2) Data processing and analysis in the lab included:
(A.) Removing sound refraction artifacts from the data (using the refraction tool in swathed) due to insufficient sound velocity profile information and varying water masses within the study area.
(B.) The measured elevations were adjusted for fluctuations in sea level during the survey by subtracting tidal elevations predicted by a tidal model and low-frequency sea level observed at the National Oceanic and Atmospheric Administration Sandy Hook tide station located at 40 degrees 28 minutes N., 74 degrees 0.6 minutes W. The tidal model utilized 9 constituents derived from a 4-month bottom pressure record obtained at Station A, located at 40 degrees 23.4 minutes N., 73 degrees 47.1 minutes W. in 38 m water depth about 2.7 km east of the HARS, during the winter of 1999-2000. An estimate of the error due to sea level remaining in the multibeam observations after the sea level correction is about 3 cm.
(C.) Two corrections have been made to the HARS multibeam data as published in Butman and others (2002). (1) The backscatter intensity data between 180-220 was stretched to 0-255 (The data published in 2002 between 180-225 was stretched to 0-255). The shaded relief data between 150-200 was stretched to 0-255 (as in the 2002 data). Aging of the multibeam transducer and software changes implemented to correct the near-nadir response make the backscatter intensity observed in 1996, 1998, and 2000 not directly comparable. Further work is needed to match the backscatter intensities between the 1996, 1998 and 2000 surveys. (2) The data were also reprocessed to correct for an error in the UNB software that projected the data on a sphere rather than on the WGS84 ellipsoid. The horizontal error in placement of the data published by Butman and others (2002) was 0 in the northwestern corner of the HARS, and reached about 12 m in the southeastern corner.
All mapped files are in the Mercator projection, having a central longitude of -75 degrees West, a latitude of true scale of 40 degrees north and the horizontal datum is WGS84. The vertical datum is mean lower low water.
Process_Date: 1996 to 2003
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: William Danforth
Contact_Organization: U.S. Geological Survey
Contact_Position: Operational Geologist
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Country: USA
Contact_Voice_Telephone: 508-548-8700 x2274
Contact_Facsimile_Telephone: 508-457-2310
Contact_Electronic_Mail_Address: bdanforth@usgs.gov
Hours_of_Service: 8 a.m. to 5 p.m. EST
Process_Step:
Process_Description: Creation of original metadata record
Process_Date: 20021216
Process_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Brad Butman
Contact_Organization: U.S. Geological Survey
Contact_Position: Oceanographer
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: MA
Postal_Code: 02543-1598
Contact_Voice_Telephone: 508-457-2212
Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method: Raster
Raster_Object_Information:
Raster_Object_Type: Pixel
Row_Count: 2487
Column_Count: 3098
Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Planar:
Map_Projection:
Map_Projection_Name: Mercator
Mercator:
Standard_Parallel: 40.0
Longitude_of_Central_Meridian: -75
False_Easting: 0
False_Northing: 0
Planar_Coordinate_Information:
Planar_Coordinate_Encoding_Method: row and column
Coordinate_Representation:
Abscissa_Resolution: 3
Ordinate_Resolution: 3
Planar_Distance_Units: meters
Geodetic_Model:
Ellipsoid_Name: World Geodetic System 84
Semi-major_Axis: 6378137
Denominator_of_Flattening_Ratio: 298.257
Vertical_Coordinate_System_Definition:
Depth_System_Definition:
Depth_Datum_Name: Mean lower low water
Depth_Resolution: 0.3
Depth_Distance_Units: Meters
Depth_Encoding_Method: Explicit depth coordinate included with horizontal coordinates
Distribution_Information:
Distributor:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Bradford Butman
Contact_Organization: U.S. Geological Survey
Contact_Position: Oceanographer
Contact_Address:
Address_Type: mailing and physical address
Address: 384 Woods Hole Road
City: Woods Hole
State_or_Province: Massachusetts
Postal_Code: 02543-1598
Country: USA
Contact_Voice_Telephone: 508-548-8700 x2212
Contact_Facsimile_Telephone: 508-457-2309
Contact_Electronic_Mail_Address: bbutman@usgs.gov
Distribution_Liability:
These data were prepared by an agency of the United States Government. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Although all data have been used by the USGS, no warranty, expressed or implied, is made by the USGS as to the accuracy of the data and/or related materials. 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.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: TIFF
Format_Version_Number: 6
Format_Information_Content: Processed imagery depicting characteristics of the sea floor
File_Decompression_Technique: unzip
Transfer_Size: 45
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Fees: none
Metadata_Reference_Information:
Metadata_Date: 20150204
Metadata_Review_Date: 20040722
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: Peter N Schweitzer
Contact_Organization: USGS Midwest Area
Contact_Position:
Collection manager, USGS Geoscience Data Clearinghouse, http://geo-nsdi.er.usgs.gov/
Contact_Address:
Address_Type: mailing address
Address:
Mail Stop 954
12201 Sunrise Valley Dr
City: Reston
State_or_Province: VA
Postal_Code: 20192-0002
Country: USA
Contact_Voice_Telephone: 703-648-6533
Contact_Facsimile_Telephone: 703-648-6252
Contact_Electronic_Mail_Address: pschweitzer@usgs.gov
Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Extensions:

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