Multibeam backscatter imagery extracted from gridded bathymetry of Maro Reef, Northwestern Hawaiian Islands, USA. These data provide coverage between 20 and 5000 meters. The backscatter dataset includes data collected using Simrad EM300, Simrad EM3002d, Simrad EM120, and Reson 8101 multibeam sonars. The sonars frequencies are 30 kHz, 300 kHz, 12 kHz, and 240 kHz respectively and the backscatter data from each sonar are processed and gridded separately. These metadata are for the 30 m grid cell size Simrad em120 multibeam backscatter data only.
This ASCII file of backscatter imagery was created using data gathered from multibeam soundings for use as a planning and reference document. The data are also being used for benthic habitat mapping, for locating Essential Fish Habitat, and for studying geologic features of the area. Refer to supplemental information for description of instrument and survey.
Multibeam data were collected aboard the R/V Kilo Moana, a 186' United States Navy owned research vessel operated by the University of Hawaii. The R/V Kilo Moana's survey sensors include a 12 kHz Simrad EM120 sonar and a 95 kHz Simrad EM1002 sonar, which provide bathymetry and imagery data, a TSS/Applanix POS/MV Model 320, which measures position, velocity, attitude and heading, and a Sippican MK-21/PC based XBT system plus a Seabird SBE 9/11 CTD both of which measured sound velocity profiles. Specific equipment configurations are documented in metadata from cruise: KM0206. These metadata can be accessed at: http://www.soest.hawaii.edu/pibhmc/cms/cruise-catalog/.
ground condition
These data are not to be used for navigation purposes. Please acknowledge NOAA and the Joint Institute for Marine and Atmospheric Research (JIMAR) University of Hawaii as the sources of this information. sources of this information.
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http://www.soest.hawaii.edu/pibhmc/NWHI_images/maro-bs_440.jpg
http://www.soest.hawaii.edu/pibhmc/NWHI_images/maro-em120-bs_440.jpg
PIBHMC, CRED, PIFSC, NOAA and JIMAR
Data are collected for resource management and research purposes and are tested for internal consistency; however, no effort is made to compare these data to external references or to other published data.
These data are believed to be logically consistent though no tests were performed
Complete
Horizontal positioning system: GPS (SPS) Horizontal position accuracy: 25 meters
1 m Range resolution of sonar ~1.25 cm Raw sounding resolution: Variable Vertical accuracy of gridded product: 1% of water depth
Multibeam data were collected using Simrad Neptune software. Multibeam data were processed using MB-System, an open source software package for the processing and display of bathymetry and backscatter imagery data. The data were destriped using mbfilter, a grazing angle correction was calculated and appplied to the data using mbbackangleold and mbanglecorrect, and the data were gridded using mbmosaic. ASCII files were created from netCDF grids using the Generic Mapping Tools (GMT). More information about MB-System and GMT can be found at: www.ldeo.columbia.edu/res/pi/MB-System/ www.soest.hawaii.edu/gmt/
Sidescan data within a Simrad file are arranged as small sequences of intensity values, one sequence per beam per ping. The intensity values represent the amplitude of echo returns to the sensor and can be related to seabed roughness.
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These data are not to be used for navigational purposes. NOAA makes no warranty regarding these data, expressed or implied, nor does the fact of distribution constitute such a warranty. NOAA cannot assume liability for any damages caused by any errors or omissions in these data, nor as a result of the failure of these data to function on a particular system.
Arc ASCII can be converted to Arc Raster using ArcToolbox Conversion Tools.
