Ginger Barth
Wayne E. Baldwin
Robert S. Reece
Sean S. Gulick
William W. Danforth
Florence L. Wong
20220825
MGL1109backsgeo.xyb: 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 XYB (longitude, latitude, backscatter) format, geographic coordinate system
raster digital data
data release
DOI: 10.5066/F7HM56HK
Pacific Coastal and Marine Science Center, Santa Cruz, California
U.S. Geological Survey
https://doi.org/10.5066/F7HM56HK
https://www.sciencebase.gov/catalog/item/560ef961e4b0ba4884c5ed25
Ginger Barth
Wayne E. Baldwin
Robert S. Reece
Sean S. Gulick
William W. Danforth
Florence L. Wong
2022
Multibeam bathymetry and acoustic backscatter data from the Alaskan region, Extended Continental Shelf Project, 2011 field season: Gulf of Alaska and Bering Sea
data release
DOI: 10.5066/F7HM56HK
Pacific Coastal and Marine Science Center, Santa Cruz, California
U.S. Geological Survey
https://doi.org/10.5066/F7HM56HK
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.
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).
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.
20110603
20110625
ground condition
None planned
-152.381751
-137.797038
57.713119
48.268275
ISO 19115 Topic Category
environment
geoscientificInformation
oceans
Data Categories for Marine Planning
Substrate
Physical Habitats and Geomorphology
USGS Thesaurus
sea-floor characteristics
multibeam sonar
marine geophysics
sea-floor acoustic reflectivity
image mosaics
geospatial datasets
Marine Realms Information Bank (MRIB) keywords
marine geophysics
seismic methods
multibeam echo sounder
continental shelf
None
U.S. Geological Survey
USGS
Coastal and Marine Hazards and Resources Program
CMHRP
Pacific Coastal and Marine Science Center
PCMSC
backscatter intensity
USGS Metadata Identifier
USGS:560ef961e4b0ba4884c5ed25
Geographic Names Information System (GNIS)
Gulf of Alaska
Bering Sea
Kodiak Island
Dutch Harbor
NGA GEOnet Names Server (GNS)
Baranof Fan
Shirshov Ridge
Kodiak Seamount
Bowie Seamount
Aleutian Trench
Umnak Plateau
Aleutian Basin
Bowers Ridge
None
Surveyor Fan
Extended Continental Shelf
None
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.
U.S. Geological Survey, Pacific Coastal and Marine Science Center
PCMSC Science Data Coordinator
mailing and physical
2885 Mission Street
Santa Cruz
CA
95060
831-427-4747
pcmsc_data@usgs.gov
https://www.sciencebase.gov/catalog/file/get/560ef961e4b0ba4884c5ed25?name=MGL1109backscat.jpg&allowOpen=true
MGL1109 acoustic backscatter, Gulf of Alaska
JPEG
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.3.1.1850
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.
No formal logical accuracy tests were conducted
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.
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.
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.
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.
201106
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, GeoTIFF, 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
201208
U.S. Geological Survey
Wayne E. Baldwin
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543-1598
USA
508-457-2226
wbaldwin@usgs.gov
Wrote version 1 of metadata.
20121018
U.S. Geological Survey
Wayne E. Baldwin
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
MA
02543-1598
USA
508-457-2226
wbaldwin@usgs.gov
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.
20220817
Susan A Cochran
U.S. Geological Survey, Pacific Coastal and Marine Science Center
Geologist
mailing and physical
2885 Mission St.
Santa Cruz
CA
95060
United States
831-460-7545
scochran@usgs.gov
Raster
Grid Cell
9559
16898
1
0.001
0.001
decimal degrees
D_WGS_84
WGS_84
6378137.0
298.257223563
Attribute Table
Table containing attribute information associated with the data set.
Producer defined
Value
backscatter intensity
Producer defined
-59.610
7.790
decibel
>
> 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
>
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.
U.S. Geological Survey - ScienceBase
mailing and physical
Denver Federal Center, Building 810, Mail Stop 302
Denver
CO
80225
1-888-275-8747
sciencebase@usgs.gov
These data are available in XYB format (Easting, Northing, dB value) format, along with CSDGM FGDC-compliant metadata.
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.
delimited text
n/a
Zip file contains the grid of backscatter as well as the associated metadata files.
207
https://www.sciencebase.gov/catalog/file/get/560ef961e4b0ba4884c5ed25
https://www.sciencebase.gov/catalog/item/560ef961e4b0ba4884c5ed25
https://doi.org/10.5066/F7HM56HK
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.
None
20220825
U.S. Geological Survey, Pacific Coastal and Marine Science Center
PCMSC Science Data Coordinator
mailing and physical
2885 Mission Street
Santa Cruz
CA
95060
831-427-4747
pcmsc_data@usgs.gov
Content Standard for Digital Geospatial Metadata
FGDC-STD-001-1998