U.S. Geological Survey Coastal and Marine Geology Program
2012
MGL1109_mos: Multibeam backscatter data collected by the U.S. Geological Survey in the Gulf of Alaska during cruise MGL1109, 100 meter gridded data in ESRI Binary Grid format
mgl1109_mos\\IGSAGIEGLTBDAX4\E$\LangsethData\MGL1109\ESRI\Grids\mgl1109_mosraster digital data
In June 2011, the U.S. Geological Survey - Coastal and Marine Geology Program 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).
This ESRI Binary Grid dataset represents approximately 69060 square kilometers of Simrad EM122 multibeam-backscatter data collected in the Gulf of Alaska during U.S. Geological Survey - Coastal and Marine Geology Program cruise MGL1109 aboard the R/V Marcus G. Lanseth. The data have been reduced for position, elevation, orientation, water-column sound-speed, and refraction effects.
md5_checksum value: e1fb45ddd89e3e5893661ec8aacc429f mgl1109_mos\w001001.adf. digestIT 2004 was used to generate the md5_checksum value, please see http://www.openoffice.org/dev_docs/using_md5sums.html#lin for more information on how to validate the md5_checksum value. For metadata pertaining to cruise MGL1109, please see http://walrus.wr.usgs.gov/infobank/l/l0911ga/html/l-09-11-ga.meta.html
en
2011-06-03
2011-06-25
publication date
None planned
-152.555183-135.65774257.81442748.255660
dB (decibel)
-59.617.79169050.0000001181550.0000005385650.0000006408050.000000
NASA > GCMD Earth Science Keywords
EARTH SCIENCE Oceans > Bathymetry/Seafloor Topography > Bathymetry
Extended Continental Shelf Project Glossary of Terms
Extended Continental Shelf
Bathymetric Survey
Uncontrolled - Departure
Kodiak, AK
Uncontrolled - Arrival
Kodiak, AK
NASA/GCMD Location Keywords
Ocean > Bering Sea
MGL1109
R/V Marcus G. Langseth (Lamont-Doherty Earth Observatory, Columbia University)
Kongsberg-Simrad EM122 Multibeam Echosounder
None
U.S. Geological Survey
Wayne Baldwin
Geologist
mailing and physical address
384 Woods Hole Rd
Woods Hole
MA
02543
USA
(508) 548-8700 x-2226
(508) 457-2310
wbaldwin@usgs.gov
9:00 AM - 5:00 PM Eastern
Wayne Baldwin - U.S. Geological Survey
None
Unclassified
None
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.3.1.1850Raster Dataset
Kongsberg-Simrad EM122 Multibeam Echosounder was used with transmit (fore-aft) and recieve (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% of water depth.
Unknown
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% 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.
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%
Style, FiltType = Blend,dB Mean
2012-08
U.S. Geological Survey
Wayne Baldwin
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
AM
02543
USA
(508) 548-8700 x2315
(508) 457-2310
wbaldwin@usgs.gov
9:00 AM - 5:00 PM Eastern
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.
2012-05
U.S. Geological Survey
Wayne Baldwin
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
AM
02543
USA
(508) 548-8700 x2315
(508) 457-2310
wbaldwin@usgs.gov
9:00 AM - 5:00 PM Eastern
U.S. Geological Survey
ground condition
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° x 1°) located along the ship centerline, and a receive unit (1° x 30°) 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.
Raster
ESRI Binary Grid
10224
10125
100
meters
100
meters
matrix valuesUpper left3211GRIDFALSEdefault255TRUE
row and column
100100
meters
Universal Transverse Mercator60.999600-147.0000000.000000500000.0000000.000000
D_WGS_84
WGS_84
6378137.0298.257223563000030000
WGS_1984_UTM_Zone_6N
GCS_WGS_1984
U.S. Geological Survey
Wayne Baldwin
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
AM
02543
USA
(508) 548-8700 x2315
(508) 457-2310
wbaldwin@usgs.gov
9:00 AM - 5:00 PM Eastern
MGL1109_mos
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.
ESRI Binary Grid
399.883399.883
None
2012-10-18
U.S. Geological Survey
Wayne Baldwin
Geologist
mailing and physical address
384 Woods Hole Road
Woods Hole
AM
02543
USA
(508) 548-8700 x2315
(508) 457-2310
wbaldwin@usgs.gov
9:00 AM - 5:00 PM Eastern
Content Standard for Digital Geospatial Metadata
FGDC-STD-012-2002
universal time
None
Unclassified
None
http://walrus.wr.usgs.gov/infobank/l/l0911ga/html/l-09-11-ga.meta.htmlenhttp://www.esri.com/metadata/esriprof80.htmlESRI Metadata Profile
20130402
14503800
2013040214062200
20130402
Microsoft Windows XP Version 5.1 (Build 2600) Service Pack 3; ESRI ArcCatalog 9.3.1.1850mgl1109_mos1690501181550640805053856501-152.555183-135.65774257.81442748.255661ISO 19115 Geographic Information - MetadataDIS_ESRI1.0datasetfile://\\IGSAGIEGLTBDAX4\E$\LangsethData\MGL1109\ESRI\Grids\mgl1109_mosLocal Area Network002399.883Raster DatasetWGS_1984_UTM_Zone_6N2110125100Meter1 Meter = 1 Meter(s)10224100Meter1 Meter = 1 Meter(s)