Daniel J. Nowacki Cordell Johnson Joshua B. Logan Andrew W. Stevens 20250709 comma-delimited text data release DOI: 10.5066/P15BS65X Pacific Coastal and Marine Science Center, Santa Cruz, California Geological Survey Suggested citation: Nowacki, D.J., Johnson, C., Logan, J.B., Stevens, A.W., 2025, Nearshore bathymetry at Point Barrow, Alaska, 2022: U.S. Geological Survey data release, https://doi.org/10.5066/P15BS65X. https://doi.org/10.5066/P15BS65X This dataset contains nearshore bathymetry measurements collected at Point Barrow, Alaska. The data were collected in July 2022 using a single beam echosounder and global navigation satellite system receiver and subsequently processed by the U.S. Geological Survey, Pacific Coastal and Marine Science Center. Results are provided in a comma-separated value format (csv). This product was created to support coastal water level modeling along the Alaska coastline. It is intended for reuse by scientists, managers, and the general public. These data can be opened with any text viewer, spreadsheet editor, or geographic information systems (GIS) software for review, visualization, and analysis purposes. Additional information about the field activity or activities from which these data were derived is available online at: https://cmgds.marine.usgs.gov/fan_info.php?fan=2022-642-FA 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 dataset in nonproprietary form, this metadata file may include some vendor-specific terminology. 20220729 20220730 ground condition at the time source data were collected Complete None planned -156.498916 -156.428817 71.396931 71.380881 USGS Metadata Identifier USGS:a1f5c532-e5f8-43bc-a31f-67a420be038e ISO 19115 Topic Category elevation USGS Thesaurus bathymetry Marine Realms Information Bank (MRIB) coast None U.S. Geological Survey USGS Coastal and Marine Hazards and Resources Program CMHRP Pacific Coastal and Marine Science Center PCMSC Geographic Names Information System (GNIS) State of Alaska North Slope Borough Point Barrow Beaufort Sea Chukchi Sea No access constraints 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(s) of the dataset and in products derived from these data. This information is not intended for navigation purposes. PCMSC Science Data Coordinator U.S. Geological Survey, Pacific Coastal and Marine Science Center mailing and physical

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Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov point_barrow_bathy_2022_browse.png Satellite image overlain with bathymetry data points collected at Point Barrow, Alaska in July 2022 PNG MATLAB Version: 9.8.0.1396136 (R2020a) No formal attribute accuracy tests were conducted. All data falls within expected ranges. Dataset is considered complete for the information presented, as described in the abstract. Users are advised to read the rest of the metadata record carefully for additional details. Horizontal positions of the survey vessel were post-processed to apply differential corrections obtained from the National Geodetic Survey Site BRW1, located approximately 17 km from the survey area. Manufacturer reported accuracy for the differentially corrected horizontal positions for the GNSS rover trajectories is 0.8 cm + 0.5 ppm, suggesting a horizontal accuracy of approximately 1.7 cm. Uncertainty in the horizontal positions associated with pitch and roll of the survey vessels is unknown. Manufacturer reported accuracy for the differentially corrected vertical positions for the GNSS rover trajectories is 1.5 cm + 1 ppm. The GNSS base station was located roughly 17 km from the survey site, suggesting the vertical accuracy of survey vessel positions to be 3.2 cm relative to the base station coordinate. Additional manufacturer reported uncertainty in the bathymetric soundings is 1 cm + 0.1 percent of water depth. Maximum water depths surveyed on this mapping mission are approximately 8 m, yielding a maximum vertical uncertainty of the bathymetric soundings of 1.8 cm. Total combined uncertainty in the bathymetric elevations is derived by summing the uncertainties from the GNSS and echosounder in quadrature, yielding a total uncertainty of approximately 3.7 cm. Uncertainty in the vertical positions associated with pitch and roll of the survey vessels is unknown. Bathymetry data were collected between July 29 and 30, 2022, using single-beam sonar systems and global navigation satellite systems (GNSS) receivers mounted on a small vessel. Depths from the echosounders were computed using sound velocity profiles measured using a CTD during the survey. Positioning of the survey vessels was determined at 10 Hz using survey-grade GNSS receivers. Output from the GNSS receivers and sonar systems were combined in real time by a computer running HYPACK hydrographic survey software. Navigation information was displayed on a video monitor, allowing vessel operators to navigate along planned survey lines. 20220729 Survey-grade positions of the vessels were achieved with a single-base station and differential post-processing. Positioning data from the GNSS receivers were post-processed using Waypoint Grafnav to apply differential corrections from the GNSS base station site BRW1 operated by the National Geodetic Survey with known horizontal and vertical coordinates relative to the North American Datum of 1983. Orthometric elevations relative to the NAVD88 vertical datum were computed using NGS Geoid18 offsets. Bathymetric data were merged with post-processed positioning data, speed of sound corrections were applied, and spurious soundings were removed using a custom Graphical User Interface (GUI) programmed with the computer program MATLAB. The final point data are projected in cartesian coordinates in NAD83(2011) / UTM zone 4N (EPSG: 6333). 20220829 All available bathymetry data from the survey were compiled into a comma-delimited text file in MATLAB for distribution. 20250625 Point Point 225311 Universal Transverse Mercator 4 0.9996 -159.0 0.0 500000.0 0.0 coordinate pair 0.6096 0.6096 meters D NAD 1983 2011 GRS 1980 6378137.0 298.257222101 North American Vertical Datum of 1988 (NAVD88) GEOID12B 0.01 meters Explicit elevation coordinate included with horizontal coordinates bathymetry_point_barrow_2022.csv Comma-separated value file Producer Defined x_meters_utmz4n X coordinate (easting) in meters NAD83(2011) / UTM zone 4N (EPSG: 6333) Producer Defined 589074.54 591559.47 meters 0.01 y_meters_utmz4n Y coordinate (northing) in meters NAD83(2011) / UTM zone 4N (EPSG: 6333) Producer Defined 7921915.89 7923235.58 meters 0.01 z_meters_navd88 Orthometric height (elevation) in meters NAVD88 GEOID12B Producer Defined -7.82 0.39 meters 0.01 These metadata describe a comma-separated value (csv) file containing bathymetry data from Point Barrow, Alaska. The first line is a header line, and each subsequent line contains x and y coordinates in meters NAD83(2011) / UTM zone 4N (EPSG: 6333) and an orthometric height (elevation) in meters NAVD88 GEOID12B. U.S. Geological Survey U.S. Geological Survey - CMGDS mailing and physical

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Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov 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. Comma-delimited text MATLAB Version: 9.8.0.1396136 (R2020a) text comma-delimited text file No compression applied 6.0 https://doi.org/10.5066/P15BS65X Data and metadata can be downloaded using the Network_Resource_Name link and scrolling down to the Sonar Data section. None These data can be opened with any text viewer, spreadsheet editor, or geographic information systems (GIS) software. 20250709 U.S. Geological Survey, Pacific Coastal and Marine Science Center PCMSC Science Data Coordinator mailing and physical

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Santa Cruz CA 95060 831-427-4747 pcmsc_data@usgs.gov Content Standard for Digital Geospatial Metadata FGDC-STD-001-1998