U.S. Geological Survey Coastal and Marine Geology Program
2012
Bering_MGL1111_EM122centerdepth.txt : Multibeam bathymetry data collected by the U.S. Geological Survey in the Bering Sea during cruise MGL1111, along track center-beam depths extracted from 100 meter gridded data in ASCII text format
In August 2011, the U.S. Geological Survey - Coastal and Marine Geology Program conducted a research cruise in the Bering Sea 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 ASCII text dataset contains center-beam dpeths for approximately 5727 trackline kilometers of Simrad EM122 multibeam-bathymetry data collected in the Bering Sea during U.S. Geological Survey - Coastal and Marine Geology Program cruise MGL1111 aboard the R/V Marcus G. Lanseth. The depth values were extracted from gridded data which were reduced for position, elevation, orientation, water-column sound-speed, and refraction effects.
For metadata pertaining to cruise MGL1111, please see http://http://walrus.wr.usgs.gov/infobank/l/l1111bs/html/l-11-11-bs.meta.html
2011-08-10
2011-09-02
publication date
None planned
297186.66
1607986.66
6659670.06
5933870.06
-3876.10
-84.76
meters
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
Dutch Harbor, AK
Uncontrolled - Arrival
Dutch Harbor, AK
NASA/GCMD Location Keywords
Ocean > Bering Sea
MGL1111
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
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 80 and 3900 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 (portions of Julian Days 233 - 240) 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.
CARIS processing for MGL1111: A new CARIS HIPS project (ver. 7.1) was created with projection information set to Universal Transverse Mercator (UTM) Zone 60N, WGS84. Each Simrad EM122 data file (*.all) was imported to the new CARIS project using the Import/Conversion Wizard. A 100 meter resolution Bathymetric and Statistical Error (BASE) Surface was created and new files were added to the surface each Julian day. With the addition of new files, the BASE surface was reviewed for any inconsistencies or data anomalies. Navigation was edited as needed using the navigation editor tool in CARIS. Filters were applied to each line including beam to beam slopes and across track angle. The CARIS "surface filter" was applied to the data using the two standard deviation option. Swath data were also edited manually to remove obviously outlying soundings.
2011-08
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 100 meter CARIS HIPS BASE surface for MGL1111 was exported from CARIS as a Bathymetric Attributed Grid (BAG) file. The resulting BAG file was used to import the surface into IVS3D DMagic as gridded data, then the surface was saved as a Fledermaus Digital Terrain Model in the IVS3D SD format. Finally, the Fledermaus ArcGIS module was used to export the surface directly to an ESRI Binary Grid.
2012-03
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
Navigation information (Easting,Northing,Longitude,Latitude,UTC Time,Year-Julian Day,SIS Filename) were extracted from the CARIS HIPS database utilizing a Perl script that ran the CARIS command 'printfnav' on all edieted EM122 data files. Unix 'cat' was used to concatonate the output nav files to a single file, 'grep' was used to exract only soundings flagged as accepted, then an 'awk' filter was used to extract records with unique navigation fixes, one per second. The resultant text file was used to create an ArcGIS point feature class (ArcMap, create feature class from XY table).
2012-03
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 navigation text file created in the previous step was used to create an ArcGIS point feature class (ArcMap, create feature class from XY table). The navigation point feature class and the ESRI binary grid 'mgl1111_bathy' were used as the point and raster inputs for the ArcGIS Spatial Analyst tool 'Extract values to points', with the interpolate values at point locations option selected. The resultant point shapefile containing "Easting,Northing,Longitude,Latitude,UTC Time,Year-Julian Day,SIS Filename,Depth (meters)" was exported to ASCII text.
2012-03
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.
Point
coordinate pair
meters
Universal Transverse Mercator
60N
0.9996
177
0
500000
0
WGS84
WGS84
WGS_1984_UTM_Zone_60N
Instantaneous sea level
Better than 1% of water depth
meters
Explicit depth coordinate included with horizontal coordinates
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
Bering_MGL1111_EM122_ASCII_100mbathy.xyz
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.
ASCII text
369
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
20121018
16155100
20121018