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David Evans and Associates, Inc. (DEA) was subcontracted by Woolpert, Inc. to provide remote technical and data processing support to hydrographic survey operations conducted by the National Oceanic and Atmospheric Administration (NOAA) in the vicinity of Bayfield Peninsula and Apostle Islands National Lakeshore (APIS) in Lake Superior. The acoustic backscatter data will support the benthic habitat mapping and modeling needs of multiple agencies including NOAA, National Park Service (NPS), Wisconsin Department of Natural Resources, and other regional partners and stakeholders. |
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David Evans and Associates, Inc. (DEA) was subcontracted by Woolpert, Inc. to provide remote technical and data processing support to hydrographic survey operations conducted by the National Oceanic and Atmospheric Administration (NOAA) in the vicinity of Bayfield Peninsula and Apostle Islands National Lakeshore (APIS) in Lake Superior. The acoustic backscatter data will support the benthic habitat mapping and modeling needs of multiple agencies including NOAA, National Park Service (NPS), Wisconsin Department of Natural Resources, and other regional partners and stakeholders. |
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David Evans and Associates Inc. (DEA), Woolpert, Inc., Cardinal Point Captains (CPC), National Oceanic Atmospheric Administration (NOAA), National Centers for Coastal Ocean Science (NCCOS), Great Lakes Research Initiative (GLRI). |
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<DIV STYLE="text-align:Left;font-size:12pt"><DIV><DIV><P><SPAN>During July-September 2020, Cardinal Point Captains (CPC) hydrographers conducted hydrographic survey operations in three survey areas located on the western side of Bayfield Peninsula in southwestern Lake Superior. Survey operations took place over three legs: Leg 1 (7/25-8/5), Leg 2 (8/25-9/2), and Leg 3 (9/16-9/28). CPC utilized the Research Vessel (R/V) </SPAN><SPAN STYLE="font-style:italic;"><SPAN>Echo</SPAN></SPAN><SPAN><SPAN>, which was equipped with a Teledyne-Reson SeaBat 7125 multibeam echosounder for simultaneously acquiring bathymetry and acoustic backscatter imagery. During survey operations, DEA provided remote technical support to assist CPC with vessel setup, system calibrations, and initial hydrographic data testing and quality control, and coordinated transfers of raw hydrographic data. </SPAN></SPAN></P><P><SPAN /><SPAN /></P><P STYLE="margin:0 0 0 0;"><SPAN>After initial data assessments were complete, the raw multibeam data were prepared for import into CARIS Hydrographic Information Processing System (HIPS) software (version 11.3.8). Upon import into CARIS HIPS software, the raw multibeam data were converted from native Teledyne-Reson s7k file format into CARIS HDCS format. The converted multibeam data were stored logically by survey day. </SPAN></P><P STYLE="margin:0 0 0 0;"><SPAN /><SPAN /></P><P STYLE="margin:0 0 0 0;"><SPAN>After position, motion, waterline, and sound velocity corrections were applied, soundings were gridded for review and directed editing. Preliminary grid resolution was 2 meters (m). Review of bathymetric data was conducted by reviewing multiple bathymetry child layers (e.g. standard deviation, density) in CARIS HIPS and using editing and QC tools to view and edit erroneous soundings (“fliers”), systematic biases, timing errors, or alignment offsets. Upon completion of directed editing, soundings were gridded at 2m and interpolated using the ArcGIS Focal Statistics tool for geospatial analysis. </SPAN></P><P><SPAN /></P><P><SPAN>Acoustic backscatter mosaics are an important piece of information when characterizing surficial seafloor features and delineating benthic habitats.</SPAN><SPAN> After completion of bathymetric data processing, review, and analysis, multibeam backscatter imagery processing was conducted using Quality Positioning Systems (QPS) Fledermaus Geocoder Toolbox (FMGT) software (version 7.9.3). Processed bathymetry data files were exported from CARIS HIPS as Generic Sensor Format (GSF) files. The FMGT workflow paired each native sonar file (Teledyne-Reson s7k format) with its processed GSF file, thus incorporating corrected position and motion data. A beam pattern correction was computed and applied to remove angular bias from the backscatter imagery. Angle Varying Gain (AVG) was applied using the standard “Flat” algorithm and window size of 300 pings. A backscatter imagery mosaic was produced using standard line weighting procedures. The backscatter mosaic was then reviewed manually for motion artifacts and/or brightness offsets. Manual editing was performed to adjust brightness values between adjacent survey lines and/or survey days using the “Head Bias” tool in QPS FMGT software. After the completion of backscatter data processing and quality review, final backscatter image mosaics were produced with pixel resolutions of 1m (as per project specifications) and 2m (Figure 4), the recommended product resolution based on sounding density. The backscatter imagery mosaics were exported in Geotiff format. The backscatter imagery mosaics are referenced to NAD83 UTM Zone 15 North with horizontal units in meters. Backscatter intensity is shown in logarithmic units of decibels (dB). </SPAN></P></DIV></DIV></DIV> |
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<DIV STYLE="text-align:Left;font-size:12pt"><P><SPAN>NOT TO BE USED FOR NAVIGATION. These data were prepared for an agency of the United States Government to conduct ecological research. Neither the United States Government nor any agency thereof, nor any of their employees, make any warranty, expressed or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed in this report, or represents that its use would not infringe privately owned rights. Reference therein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. Any views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. Although all data have been used by NOAA, no warranty, expressed or implied, is made by NOAA as to the accuracy of the data and/or related materials. The act of distribution shall not constitute any such warranty, and no responsibility is assumed by NOAA in the use of these data or related materials.</SPAN></P></DIV> |
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title:
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Backscatter (2m Interpolated): Bark Point to Apostle Islands National Lakeshore, Bayfield County, WI |
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["Backscatter","Lake Bottom","Great Lakes","Lake Superior","Bayfield Peninsula","Wisconsin","Apostle Islands National Lakeshore","Great Lakes Research Initiative","NOAA","NCCOS","National Park Service","Wisconsin Department of Natural Resources","Benthic Habitat Mapping","Reson 7125","R/V Echo"] |
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