Metadata: Identification_Information: Citation: Citation_Information: Originator: Ginger Barth Originator: Wayne E. Baldwin Originator: Robert S. Reece Originator: Sean S. Gulick Originator: William W. Danforth Originator: Florence L. Wong Publication_Date: 20220825 Title: MGL1109backsgeo.asc: Multibeam backscatter data collected by the U.S. Geological Survey in the Gulf of Alaska in 2011 during cruise MGL1109, 100-meter gridded data in Esri gridascii format, geographic coordinate system Geospatial_Data_Presentation_Form: raster digital data Series_Information: Series_Name: data release Issue_Identification: DOI: 10.5066/F7HM56HK Publication_Information: Publication_Place: Pacific Coastal and Marine Science Center, Santa Cruz, California Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.5066/F7HM56HK Online_Linkage: https://www.sciencebase.gov/catalog/item/560ef844e4b0ba4884c5ed1e Larger_Work_Citation: Citation_Information: Originator: Ginger Barth Originator: Wayne E. Baldwin Originator: Robert S. Reece Originator: Sean S. Gulick Originator: William W. Danforth Originator: Florence L. Wong Publication_Date: 2022 Title: Multibeam bathymetry and acoustic backscatter data from the Alaskan region, Extended Continental Shelf Project, 2011 field season: Gulf of Alaska and Bering Sea Series_Information: Series_Name: data release Issue_Identification: DOI: 10.5066/F7HM56HK Publication_Information: Publication_Place: Pacific Coastal and Marine Science Center, Santa Cruz, California Publisher: U.S. Geological Survey Online_Linkage: https://doi.org/10.5066/F7HM56HK Description: Abstract: This raster dataset represents approximately 69,060 square kilometers of Simrad EM122 multibeam-backscatter data collected in the Gulf of Alaska during U.S. Geological Survey (USGS) cruise MGL1109 aboard the R/V Marcus G. Langseth. The data have been reduced for position, elevation, orientation, water-column sound-speed, and refraction effects. Purpose: In June 2011, the U.S. Geological Survey (USGS) conducted a research cruise in the Gulf of Alaska aboard the R/V Marcus G. Langseth (Lamont-Doherty Earth Observatory, Columbia University) as part of the U.S. Extended Continental Shelf Project. The mission focused primarily on obtaining geophysical data (multichannel and CHIRP seismic reflection, ocean bottom seismometry, multibeam bathymetry, sonobuoy, XBT and XCTD) for the purposes of determining geologic framework, crustal nature, and sediment thickness in support of delineating the U.S. Extended Continental Shelf under provisions contained in Article 76 of the United Nations Convention on the Law of the Sea (UNCLOS). Supplemental_Information: Additional information about the USGS field activities from which these data were derived is available online at: https://cmgds.marine.usgs.gov/fan_info.php?fan=L0911GA https://cmgds.marine.usgs.gov/fan_info.php?fan=2011-034-FA Additional information about the Lamont-Doherty field activities from which these data were derived is available online at: https://www.rvdata.us/search/cruise/MGL1108 https://www.rvdata.us/search/cruise/MGL1109 Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this Federal Geographic Data Committee-compliant metadata file is intended to document the data set in nonproprietary form, as well as in Esri format, this metadata file may include some Esri-specific terminology. Time_Period_of_Content: Time_Period_Information: Range_of_Dates/Times: Beginning_Date: 20110603 Ending_Date: 20110625 Currentness_Reference: ground condition Status: Progress: Complete Maintenance_and_Update_Frequency: None planned Spatial_Domain: Bounding_Coordinates: West_Bounding_Coordinate: -152.381751 East_Bounding_Coordinate: -137.797038 North_Bounding_Coordinate: 57.713119 South_Bounding_Coordinate: 48.268275 Keywords: Theme: Theme_Keyword_Thesaurus: ISO 19115 Topic Category Theme_Keyword: environment Theme_Keyword: geoscientificInformation Theme_Keyword: oceans Theme: Theme_Keyword_Thesaurus: Data Categories for Marine Planning Theme_Keyword: Substrate Theme_Keyword: Physical Habitats and Geomorphology Theme: Theme_Keyword_Thesaurus: USGS Thesaurus Theme_Keyword: sea-floor characteristics Theme_Keyword: multibeam sonar Theme_Keyword: marine geophysics Theme_Keyword: sea-floor acoustic reflectivity Theme_Keyword: image mosaics Theme_Keyword: geospatial datasets Theme: Theme_Keyword_Thesaurus: Marine Realms Information Bank (MRIB) keywords Theme_Keyword: marine geophysics Theme_Keyword: seismic methods Theme_Keyword: multibeam echo sounder Theme_Keyword: continental shelf Theme: Theme_Keyword_Thesaurus: None Theme_Keyword: U.S. Geological Survey Theme_Keyword: USGS Theme_Keyword: Coastal and Marine Hazards and Resources Program Theme_Keyword: CMHRP Theme_Keyword: Pacific Coastal and Marine Science Center Theme_Keyword: PCMSC Theme_Keyword: backscatter intensity Theme: Theme_Keyword_Thesaurus: USGS Metadata Identifier Theme_Keyword: USGS:560ef844e4b0ba4884c5ed1e Place: Place_Keyword_Thesaurus: Geographic Names Information System (GNIS) Place_Keyword: Gulf of Alaska Place_Keyword: Bering Sea Place_Keyword: Kodiak Island Place_Keyword: Dutch Harbor Place: Place_Keyword_Thesaurus: NGA GEOnet Names Server (GNS) Place_Keyword: Baranof Fan Place_Keyword: Shirshov Ridge Place_Keyword: Kodiak Seamount Place_Keyword: Bowie Seamount Place_Keyword: Aleutian Trench Place_Keyword: Umnak Plateau Place_Keyword: Aleutian Basin Place_Keyword: Bowers Ridge Place: Place_Keyword_Thesaurus: None Place_Keyword: Surveyor Fan Place_Keyword: Extended Continental Shelf Access_Constraints: None Use_Constraints: USGS-authored or produced data and information are in the public domain from the U.S. Government and are freely redistributable with proper metadata and source attribution. Please recognize and acknowledge the U.S. Geological Survey as the originator of the dataset and in products derived from these data. This information is not intended for navigation purposes. Point_of_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, Pacific Coastal and Marine Science Center Contact_Person: PCMSC Science Data Coordinator Contact_Address: Address_Type: mailing and physical Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-427-4747 Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov Browse_Graphic: Browse_Graphic_File_Name: https://www.sciencebase.gov/catalog/file/get/560ef844e4b0ba4884c5ed1e?name=MGL1109backscat.jpg&allowOpen=true Browse_Graphic_File_Description: MGL1109 acoustic backscatter, Gulf of Alaska Browse_Graphic_File_Type: JPEG Native_Data_Set_Environment: Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.3.1.1850 Cross_Reference: Citation_Information: Originator: David W. Caress Originator: Dale N. Chayes Publication_Date: 2006 Title: MB-System source code Online_Linkage: https://www3.mbari.org/data/mbsystem/html/mbsystem_home.html Data_Quality_Information: Attribute_Accuracy: Attribute_Accuracy_Report: Kongsberg-Simrad EM122 Multibeam Echosounder was used with transmit (fore-aft) and receive (athwart ships) beam widths of 1 degree, with swaths of 3-4 times water depth in water depths between 50 and 6000 m. Depth accuracies not determined, however Kongsberg-Simrad state that the system is capable of depth accuracies approaching 0.2 percent of water depth. Logical_Consistency_Report: No formal logical accuracy tests were conducted Completeness_Report: Raw EM122 Multibeam Echosounder data collected during OBS operations were not used in the generation of this gridded dataset because OBS instruments were deployed along transects coincident with previously surveyed ship track. Upon inspection in CARIS during post-processing it was deemed appropriate to exclude the redundant data from the gridding process. Positional_Accuracy: Horizontal_Positional_Accuracy: Horizontal_Positional_Accuracy_Report: Horizontal positioning of the vessel was determined using a Kongsberg Seapath 300 series integrated inertial motion and positioning system. Positioning is accurate to better than 5 meters (at 95 percent confidence) during all surveying. All positioning is referenced to the WGS84 Datum. Vertical_Positional_Accuracy: Vertical_Positional_Accuracy_Report: No attempt was made to determine the accuracy of the system although recorded depths are typically within +/-10 m of the center-beam multibeam sounding. Lineage: Process_Step: Process_Description: Multibeam bathymetry and backscatter data were collected using a 12 kHz Kongsberg Simrad EM-122 multibeam echosounder and SIS (v3.8.2) acquisition software. The system consists of two hull-mounted transducer arrays, a transmit unit (150 deg. x 1 deg.) located along the ship centerline, and a receive unit (1 deg. x 30 deg.) that is abaft and oriented athwart-ships. The transducer pod is tilted 4 degrees towards the bow to reduce noise from cavitation and bubbles. The system forms a swath of 288 beams that produce an across-track profile of 432 soundings. The SIS software processes range/angle data from each ping during acquisition, merging position, inertial-motion, and sound-velocity data to derive a solution for vessel motion and raybending, and calculate sounding depths and positions. Sound velocity information entered into SIS was obtained from the Applied Micro Systems Micro SV mounted on the transducer pod and 52 XBT profiles. XBT profiles were extended to 12 km depth with data generated by the unix program 'mblevitus', a module of the multibeam processing package MB-System (Caress and Chayes, 2006). Average water column salinity of 34.4 ppt was determined by extrapolating data from XCDT casts. Multibeam data were collected nearly continuously throughout the cruise, effectively mapping the seafloor along the course of the ship's track. Beam angle was set at 70 on each side throughout the program and swath widths were generally between 3 and 4 times water depth. SIS logged bathymetry and backscatter solutions to the Simrad '.all' format for archival purposes. Process_Date: 201106 Process_Step: Process_Description: EM122 backscatter was processed and mosaicked using the FMGeocoder module in IVS Fledermaus. The Automatic Processing option (Mosaic only) was utilized with the EM122 Beam Time Series (from *.all raw files) selected as the backscatter source. A single tile mosaic, with 100 m per pixel resolution, was created for the entire survey area. The final mosaic was exported to these file formats: Fledermaus SD, ESRI ASCII Raster, and XYB format (Easting, Northing, dB value). The following project setup and processing parameters were specified: Project Coordinate System: Horiz. CS: WGS84,UTM,Zone 6N Custom Survey Area: XMIN,YMIN,XMAX,YMAX = 169100, 5385700, 1181500, 6408000 EM122 Sensor Config: Tx1:Xoff,Yoff,Zoff,Roff,Poff,Yoff = 20.92,0.57,8.46,0.16,-0.08,359.99 Tx2:Xoff,Yoff,Zoff,Roff,Poff,Yoff = 16.07,0.05,8.53,0.16,-0.08,0 IMU:Xoff,Yoff,Zoff,Roff,Poff,Yoff,lat = 0,0,0,-0.51,-0.23,0.43,0 Line Processing Parameters: Backscatter: Apply Beam Pattern Correction Beam Angle Cutoffs: start,cut = 0, 90 Backscatter Range: Calibrated,Min,Max = -70,10 AVG: Apply AVG - Flat Algorithm - Window Size 30 Statistics: Log space (dB) Navigation: Linear Interp. Format: Kongsberg(.all) Navigation Src.: Use Default Dual Swath Comp.: First O Sonar Defaults: Default Vals - Custom Override All - Sonar Type: Simrad EM122 MBES PrimFrq,SecFrq,MAN,MNB,ATBW,CTBW,SSS = 12000,0,120,484,2,4,1500 PusleL,PSR,SSR,Spread,TxPwr,RecGain,Abs = 5000,1001,0,0,1,1,30 Mosaicking Parameters: Line Blending = 50 percent Style, FiltType = Blend,dB Mean Process_Date: 201208 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Wayne E. Baldwin Contact_Position: 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: 508-457-2226 Contact_Electronic_Mail_Address: wbaldwin@usgs.gov Process_Step: Process_Description: The output ESRI ASCII Raster file was imported as a floating point grid into ArcGIS 9.3 using the ASCII to Raster tool selected from the Conversion Tools - To Raster toolbox. Process_Date: 201208 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Wayne E. Baldwin Contact_Position: 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: 508-457-2226 Contact_Electronic_Mail_Address: wbaldwin@usgs.gov Process_Step: Process_Description: Wrote version 1 of metadata. Process_Date: 20121018 Process_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey Contact_Person: Wayne E. Baldwin Contact_Position: 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: 508-457-2226 Contact_Electronic_Mail_Address: wbaldwin@usgs.gov Process_Step: Process_Description: Metadata was modified to bring up to current USGS PCMSC standards. Point of Contact and Metadata Contact information was updated. Keywords were added and refined. Cross Reference citation added. Details about different Network Resource Name links was given in the Access Instructions section. Minor typos were corrected. No data information was changed. Process_Date: 20220817 Process_Contact: Contact_Information: Contact_Person_Primary: Contact_Person: Susan A Cochran Contact_Organization: U.S. Geological Survey, Pacific Coastal and Marine Science Center Contact_Position: Geologist Contact_Address: Address_Type: mailing and physical Address: 2885 Mission St. City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Country: United States Contact_Voice_Telephone: 831-460-7545 Contact_Electronic_Mail_Address: scochran@usgs.gov Spatial_Data_Organization_Information: Direct_Spatial_Reference_Method: Raster Raster_Object_Information: Raster_Object_Type: Grid Cell Row_Count: 9559 Column_Count: 16898 Vertical_Count: 1 Spatial_Reference_Information: Horizontal_Coordinate_System_Definition: Geographic: Latitude_Resolution: 0.001 Longitude_Resolution: 0.001 Geographic_Coordinate_Units: decimal degrees Geodetic_Model: Horizontal_Datum_Name: D_WGS_84 Ellipsoid_Name: WGS_84 Semi-major_Axis: 6378137.0 Denominator_of_Flattening_Ratio: 298.257223563 Entity_and_Attribute_Information: Detailed_Description: Entity_Type: Entity_Type_Label: Attribute Table Entity_Type_Definition: Table containing attribute information associated with the data set. Entity_Type_Definition_Source: Producer defined Attribute: Attribute_Label: Value Attribute_Definition: backscatter intensity Attribute_Definition_Source: Producer defined Attribute_Domain_Values: Range_Domain: Range_Domain_Minimum: -59.610 Range_Domain_Maximum: 7.790 Attribute_Units_of_Measure: decibel Overview_Description: Entity_and_Attribute_Overview: > > Cell Size = 0.001 degree > Data Type: Floating Point > Number of Rows = 9559 > Number of Columns = 16898 > > BOUNDARY (WGS84, excluding NODATA): > Xmin = -152.382 > Xmax = -137.797 > Ymin = 48.268 > Ymax = 57.713 > > BOUNDARY (converted from UTM zone 6 coordinates) > Xmin = -152.555 > Xmax = -135.657 > Ymin = 48.256 > Ymax = 57.815 > > STATISTICS (decibels) > > Minimum Value = -59.610 > Maximum Value = 7.790 > Mean = -27.752 > Standard Deviation = 2.751 > > COORDINATE SYSTEM DESCRIPTION > > Projection GEOGRAPHIC > Datum WGS84 > Units DD > Spheroid WGS84 > Entity_and_Attribute_Detail_Citation: The entity and attribute information was generated by the individual and/or agency identified as the originator of the data set. Please review the rest of the metadata record for additional details and information. Distribution_Information: Distributor: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey - ScienceBase Contact_Address: Address_Type: mailing and physical Address: Denver Federal Center, Building 810, Mail Stop 302 City: Denver State_or_Province: CO Postal_Code: 80225 Contact_Voice_Telephone: 1-888-275-8747 Contact_Electronic_Mail_Address: sciencebase@usgs.gov Resource_Description: These data are available in ASCII GRID format, along with CSDGM FGDC-compliant metadata. Distribution_Liability: Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. Standard_Order_Process: Digital_Form: Digital_Transfer_Information: Format_Name: Esri grid format Format_Version_Number: Esri ArcGIS 10.2.2 Format_Information_Content: Zip file contains the asciigrid of backscatter as well as the associated metadata file. Transfer_Size: 40 Digital_Transfer_Option: Online_Option: Computer_Contact_Information: Network_Address: Network_Resource_Name: https://www.sciencebase.gov/catalog/file/get/560ef844e4b0ba4884c5ed1e Network_Resource_Name: https://www.sciencebase.gov/catalog/item/560ef844e4b0ba4884c5ed1e Network_Resource_Name: https://doi.org/10.5066/F7HM56HK Access_Instructions: Data can be downloaded using the Network Resource Links. The first link is a direct link to download a zipped file with the data and metadata. The second link is to the page containing the data. The third link is to the publication landing page. Fees: None Metadata_Reference_Information: Metadata_Date: 20220825 Metadata_Contact: Contact_Information: Contact_Organization_Primary: Contact_Organization: U.S. Geological Survey, Pacific Coastal and Marine Science Center Contact_Person: PCMSC Science Data Coordinator Contact_Address: Address_Type: mailing and physical Address: 2885 Mission Street City: Santa Cruz State_or_Province: CA Postal_Code: 95060 Contact_Voice_Telephone: 831-427-4747 Contact_Electronic_Mail_Address: pcmsc_data@usgs.gov Metadata_Standard_Name: Content Standard for Digital Geospatial Metadata Metadata_Standard_Version: FGDC-STD-001-1998