Metadata: Identification_Information: Citation: Citation_Information: Originator: Center for Coastal & Ocean Mapping, University of New Hampshire Publication_Date: March 2009 Title: ASCII xyb Multibeam Acoustic Backscatter values Data Florida Escarpment, U.S. Gulf of Mexico Description: Abstract: Full coverage, processed multibeam bathymetry acoustic backscatter data - Data were calibrated to the outgoing signal strength, receiver gains, spherical spreading and attenuation and converted from decibel (dB) to 8-bit digital number (DN). The data are provided in a cleaned fully integrated form in ASCII longitude, latitude, backscatter value. Purpose: The National Oceanic and Atmospheric Administration (NOAA), on behalf of the United States Government, has a requirement to carry out surveys of specific regions on the continental margin (slope and rise) in the U.S. Gulf of Mexico in order to obtain multibeam bathymetry. These data are required to support any potential claim for extended jurisdiction by the United States under United Nations Convention on the Law of the Sea (UNCLOS) Article 76. The requirement is for the collection and processing of full-coverage multibeam sonar data in water depths of approximately 2000 to 5000 m in order to precisely define the location of the 2500-m isobath and the "foot of the slope" as defined under UNCLOS Article 76. As part of their NOAA-funded research program, University of New Hampshire (UNH) researchers oversaw data acquisition, processing and archiving of the data collected during the cruise. Supplemental_Information: Information about UNH Center for Coastal and Ocean Mapping field activity are online at http://www.jhc.unh.edu/unclos/html/reports.htm. Purpose: The National Oceanic and Atmospheric Administration (NOAA), on behalf of the United States Government, has a requirement to carry out surveys of specific regions on the continental margin (slope and rise) in the northern Gulf of Mexico in order to obtain multibeam bathymetry and co-registered calibrated acoustic backscatter. These data are required to support any potential claim for extended jurisdiction by the United States under United Nations Convention on the Law of the Sea (UNCLOS) Article 76. The requirement is for the collection and processing of high quality, full-coverage multibeam sonar data in water depths of approximately 1000 to 3400 m in order to precisely define the location of the 2500-m isobath and the "foot of the slope" as defined under UNCLOS Article 76. As part of their NOAA-funded research program, University of New Hampshire (CCOM/UNH) researchers oversaw data acquisition, processing and archiving of the data collected during the cruise. Supplemental_Information: Information about UNH Center for Coastal and Ocean Mapping field activity are online at http://www.jhc.unh.edu/unclos/html/reports.htm. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 2007 Ending_Date: 2007 Status: Progress: Complete Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -85.9666667 East_Bounding_Coordinate: -84.440666 North_Bounding_Coordinate: 27.368299 South_Bounding_Coordinate: 24.833300 Bouding_Coordinate_Units: Decimal Degree Keywords: Theme: Theme_Keyword: Multibeam Theme_Keyword: Acoustic Backscatter Theme_Keyword: ASCII xyb Theme_Keyword: Continental Slope Place: Place_Keyword: Continental Margin Place_Keyword: Gulf of Mexico Place_Keyword: Northeast Gulf of Mexico Place_Keyword: Florida Escarpment Place_Keyword: Foot of the Slope Access_Constraints: None Use_Constraints: Please recognize the University of New Hampshire, Center for Coastal & Ocean Mapping (UNH/CCOM) as the source of this information. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: for Coastal & Ocean Mapping, University of New Hampshire Contact_Person: James V. Gardner Contact_Position: Research Professor Contact_Address: Address_Type: mailing and physical address Address: Chase Ocean Engineering Lab, 24 Colovos Road City: Durham State_or_Province: NH Postal_Code: 03824 Country: USA Contact_Voice_Telephone: 603-862-3473 Contact_Facsimile_Telephone: 603-862-0839 Contact_Electronic_Mail_Address: jim.gardner@unh.edu Hours_of_Service: 9 AM - 5 PM EST Security_Information: Security_Classification: Unclassified Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Attribute_Accuracy_Report: A Kongsberg Simrad EM120 12-kHz multibeam sonar was used with effective beam widths no greater than 1° x 2° (transmit fore-aft x receive athwart ship) at -3 dB, with swaths of ~7.4 times water depth in water depths between 1000 and 3400 m, with depth accuracies of the swath of better than ±0.3% of water depth at these depths. All data meets this specification. Descriptions of the systems and offsets applied can be found within the cruise report at http://ccom.unh.edu/unclos/reports.htm. In addition to bathymetry data, full time-series backscatter values were recorded across each beam footprint. Backscatter values were corrected for outgoing signal strength, receiver gains, spherical spreading, and attenuation. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report:Horizontal_Positional_Accuracy_Report: Horizontal positioning of the vessel was determined using C&C Technologies C-Nav Real Time Gypsy (RTG)-aided DGPS integrated into a TSS DMS-05 motion sensor. Positioning is accurate to better than 0.1 meters (at 95% confidence) during all surveying. All positioning is referenced to the WGS84 Datum. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: 1% of Water Depth Lineage: Process_Step: Process_Description: Individual acoustic backscatter values were extracted after data cleaning, formatted to ASCII xyb (longitude latitude backscatter) and compressed using WinZip. Process_Date: 2007 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Center for Coastal & Ocean Mapping, University of New Hampshire Contact_Person: James V. Gardner Contact_Position: Research Professor Contact_Address: Address_Type: Mailing and Physical Address Address: Chase Ocean Engineering Lab, 24 Colovos Road City: Durham State_or_Province: NH Postal_Code: 03824 Country: USA Contact_Voice_Telephone: 603-862-3473 Contact_Facsimile_Telephone: 603-862-0839 Contact_Electronic_Mail_Address: jim.gardner@unh.edu Hours_of_Service: 9 AM - 5 PM EST Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Point Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Planar: Map_Projection: Map_Projection_Name: unprojected geographic Coordinate_Information: Abscissa_Resolution: Ordinate_Resolution: Planar_Distance_Units: degrees Geodetic_Model: Horizontal_Datum_Name: WGS84 Ellipsoid_Name: WGS84 Semi-major_Axis: Denominator_of_Flattening_Ratio: Vertical_Coordinate_System_Definition: Altitude_System_Definition: Backscatter_Coordinate_System_Definition: 8-bit digital number (DN) Backscatter_Coordinate_System_Definition: DN = 255+(2*DB) DB in decibels Depth_System_Definition: Depth_Datum_Name: Depth_Resolution: Depth_Distance_Units: DN (8-bit digital number) Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: Center for Coastal & Ocean Mapping, University of New Hampshire Contact_Person: James V. Gardner Contact_Position: Research Professor Contact_Address: Mailing and Physical Address Address: Chase Ocean Engineering Lab, 24 Colovos Road City: Durham State_or_Province: NH Postal_Code: 03824 Country: USA Contact_Voice_Telephone: 603-862-3473 Contact_Facsimile_Telephone: 603-862-0839 Contact_Electronic_Mail_Address: jim.gardner@unh.edu Hours_of_Service: 9 AM - 5 PM EST Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: ASCII Winzip compressed Format_Information_Content: Individual Beam Acoustic Backscatter Values (longitude, latitude, backscatter) File_Decompression_Technique: Winzip Transfer_Size: 56.70 MB compressed Metadata_Reference_Information: Metadata_Date: 2007 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: Center for Coastal & Ocean Mapping, University of New Hampshire Contact_Person: James V. Gardner Contact_Position: Research Professor Contact_Address: Mailing and Physical Address Address: Chase Ocean Engineering Lab, 24 Colovos Road City: Durham State_or_Province: NH Postal_Code: 03824 Country: USA Contact_Voice_Telephone: 603-862-3473 Contact_Facsimile_Telephone: 603-862-0839 Contact_Electronic_Mail_Address: jim.gardner@unh.edu Hours_of_Service: 9 AM - 5 PM EST Metadata_Standard_Name: FGDC Content Standard for Digital Geospatial Metadata ("CSDGM version 2") Metadata_Standard_Version: FGDC-STD-001-1998 Metadata_Time_Convention: Local Time Metadata_Security_Information: Metadata_Security_Classification: Unclassified