Storm impact survey data for selected Alaska coastal communities in response to Extra-Tropical Cyclone Merbok, September 2022

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Frequently anticipated questions:


What does this data set describe?

Title:
Storm impact survey data for selected Alaska coastal communities in response to Extra-Tropical Cyclone Merbok, September 2022
Abstract:
Storm impact survey data for selected Alaska coastal communities in response to Extra-Tropical Cyclone Merbok, September 2022, Raw Data File 2022-14, presents Global Navigation Satellite System (GNSS) high-water mark (HWM) locations and elevations, coastal profile transects, observed erosion evidence, and ground elevation points for the communities of Golovin, Hooper Bay, Newtok, Nome, Shaktoolik, Stebbins, and Teller, Alaska. These data were collected in the wake of Extra-Tropical Storm Merbok between September 19 and September 23, 2022 by Alaska Division of Geological & Geophysical Surveys (DGGS), with assistance from the Alaska Division of Mining, Land and Water (DMLW) and the U.S. Geological Survey (USGS). The GNSS positional data were collected to assess coastal impacts from the storm. The data are available from the DGGS website: http://doi.org/10.14509/30909.
Supplemental_Information:
High-water marks:    High-water mark locations and elevations; HWM points were collected using methods consistent with USGS (Koenig and others, 2016) and U.S. Army Corps of Engineers (USACE, 2012) guidance.	
Coastal profile:    Coastal profile transect locations and elevations. Coastal profiles were collected along historical transects that can be viewed on the DGGS Alaska Coastal Profile Tool (ACPT) found at https://maps.dggs.alaska.gov/acpt/.	
Ground and erosion points:    Locations and elevations of observed erosion evidence.
  1. How might this data set be cited?
    Horen, K.C., Poisson, A.C., Siemsen, Z.J., Donohue, J.M., Widmer, K.L., Adams, J.D., and Overbeck, J.R., 2022, Storm impact survey data for selected Alaska coastal communities in response to Extra-Tropical Cyclone Merbok, September 2022: Raw Data File RDF 2022-14, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 10 p.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -162.291435
    East_Bounding_Coordinate: -162.278200
    North_Bounding_Coordinate: 63.523833
    South_Bounding_Coordinate: 63.517672
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
    Calendar_Date: 23-Sep-2022
    Currentness_Reference:
    publication date
  5. What is the general form of this data set?
    Geospatial_Data_Presentation_Form: table
  6. How does the data set represent geographic features?
    1. How are geographic features stored in the data set?
      This is a point data set.
    2. What coordinate system is used to represent geographic features?
      Grid_Coordinate_System_Name: Universal Transverse Mercator
      Universal_Transverse_Mercator:
      UTM_Zone_Number: 3
      Transverse_Mercator:
      Scale_Factor_at_Central_Meridian: 0.999600
      Longitude_of_Central_Meridian: -165
      Latitude_of_Projection_Origin: 0
      False_Easting: 500000.000000
      False_Northing: 0
      Planar coordinates are encoded using coordinate pair
      Abscissae (x-coordinates) are specified to the nearest .00000001
      Ordinates (y-coordinates) are specified to the nearest .00000001
      Planar coordinates are specified in Meters
      The horizontal datum used is NAD83 (2011).
      The ellipsoid used is GRS 80.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257222101.
      Vertical_Coordinate_System_Definition:
      Altitude_System_Definition:
      Altitude_Datum_Name: NAVD88, GEOID12B
      Altitude_Resolution: 0.001
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:
      Explicit elevation coordinate included with horizontal coordinates
  7. How does the data set describe geographic features?
    rdf2022-14-hwm-stebbins-20220923.csv, rdf2022-14-hwm-data-dictionary.csv
    High-water mark locations and elevations; HWM points were collected using methods consistent with USGS (Koenig and others, 2016) and U.S. Army Corps of Engineers (USACE, 2012) guidance. (Source: DGGS, DMLW, and USGS staff)
    rdf2022-14-profile-stebbins-20220923.csv, rdf2022-14-profile-data-dictionary.csv
    Coastal profile transect locations and elevations. Coastal profiles were collected along historical transects that can be viewed on the DGGS Alaska Coastal Profile Tool (ACPT) found at https://maps.dggs.alaska.gov/acpt/. (Source: DGGS)
    rdf2022-14-erosion-stebbins-20220923.csv, rdf2022-14-erosion-data-dictionary.csv
    Locations and elevations of observed erosion evidence. (Source: USGS, DGGS)

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
  2. Who also contributed to the data set?
    These data products were funded by the Alaska State Emergency Operations Center at the Alaska Division of Homeland Security and Emergency Management. The views and conclusions contained in this document are those of the authors and should not be interpreted as representing the opinions or policies of the Alaska Division of Geological & Geophysical Surveys, the Alaska Division of Mining, Land and Water, or the U.S. Geological Survey. Mention of trade names or commercial products does not constitute their endorsement by the Alaska Division of Geological & Geophysical Surveys, the Alaska Division of Mining, Land and Water, or the U.S. Geological Survey.
  3. To whom should users address questions about the data?
    Alaska Division of Geological & Geophysical Surveys
    Metadata Manager
    3354 College Road
    Fairbanks, AK
    USA

    (907)451-5020 (voice)
    (907)451-5050 (FAX)
    dggspubs@alaska.gov
    Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays
    Contact_Instructions:
    Please view our website (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.

Why was the data set created?

The GNSS positional data were collected between September 19 and September 23, 2022 to assess coastal impacts from Extra-Tropical Storm Merbok.

How was the data set created?

  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
    Date: 2022 (process 1 of 4)
    Field collection - The first team, consisting of one DGGS and one DMLW staff member, was deployed to Nome on September 19, 2022, and traveled to Golovin, Teller, and Shaktoolik. This team was equipped with two Trimble R12 receivers, using one as a base station and the other as a ground rover. The second team, consisting of one DGGS and one USGS staff member, was deployed to Bethel on September 19, 2022, and traveled to Hooper Bay and Stebbins. This team was equipped with one Trimble R10 base station receiver and one Trimble R8s ground rover receiver. The third team, consisting of one DGGS and one DMLW staff member, was deployed to Bethel on September 19, 2022, and traveled to Newtok. This team was equipped with one Trimble R10 base station receiver and one R12 ground rover receiver, using one as a base station and the other as a ground rover. Data in Nome and Teller were collected in horizontal coordinate system NAD83 (2011) Alaska State Plane Zone 8 in U.S. Survey Feet. Data in Shaktoolik, as well as HWM data in Golovin, were collected in horizontal coordinate system NAD83 (2011) Alaska State Plane Zone 7 in U.S. Survey Feet. Golovin HWM data and all data in Nome, Teller, and Shaktoolik were collected in vertical datum NAVD88 (GEOID12B) in U.S. Survey feet. Data in Newtok, Hooper Bay, and Stebbins, as well as coastal profile data in Golovin, were collected in horizontal coordinate system NAD83 (2011) UTM 3 North in meters. Data in Newtok were collected in vertical datum MLLW in meters. Golovin coastal profile data and all data in Hooper Bay and Stebbins were collected in vertical datum NAVD88 (GEOID12B) in meters.
    Date: 23-Sep-2022 (process 2 of 4)
    Ground survey - The field team arrived in Stebbins on September 23, 2022, and conducted a GNSS survey from approximately 2:30 PM to 5:45 PM AKDT. A base station was set up over a recovered temporary benchmark established during DGGS field work on July 10, 2022. This provided RTK corrections to the ground rover. The team photographed and measured 36 HWM points, recording the GNSS position, type of high water feature, height above ground (if applicable), and description of each mark. They also collected 64 ground elevation and erosion points, as well as two coastal profile transects (37 points).
    Date: 2022 (process 3 of 4)
    Data processing - Base positions were corrected using Online Positioning User Service (OPUS) solutions, which were used to update the ground rover positions using post-processed kinematic base-line adjustments in Trimble Business Center. Finalized GNSS position data were exported and formatted in accordance with the data dictionary metadata files associated with each of these data products.
    Date: 2022 (process 4 of 4)
    Data formatting - All data are delivered in comma delimited (CSV) format with column headers and are accompanied by a data dictionary detailing the header names, definitions, and applicable units. All data include field point identification numbers; UTM zone designations in two-digit number and hemisphere format (e.g., 03N); northing and easting coordinates reported to the ten-thousandth of a meter; heights (where applicable) and elevations reported to the thousandth of a meter; horizontal and vertical precision reported to the ten-thousandth of a meter; the date of collection in two-digit month, two-digit day, and four-digit year format; and long-form notes. HWM and erosion data also include feature codes. Profile data are populated with additional headers to more closely match historical ACPT formatting. These include profile name based on location (community) and profile number (e.g., Golovin_003); unique line identification incorporating location, profile number, and date (four-digit year, two-digit month, and two-digit day) (e.g., Golovin_003_20220920); location identification (community); line number; point number along profile line, beginning with 1, in ascending order from seaward extent to landward extent; vertical datum; collector(s) in first initial and last name format (e.g., Z. Siemsen); and field collection method (all points were collected using differential Global Positioning System and coded as DGPS). All data were processed and delivered in horizontal coordinate system NAD83 (2011) UTM in meters and vertical datum NAVD88 (GEOID12B) in meters; UTM Zone is indicated as an attribute in each data product.
  3. What similar or related data should the user be aware of?
    Staff, DGGS, 2014, Alaska Coastal Profile Tool (ACPT): Digital Data Series DDS 7, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Buzard, R.M., Overbeck, J.R., Chriest, Jonathan, Endres, K.L., and Plumb, E.W., 2021, Coastal flood impact assessments for Alaska communities: Report of Investigation RI 2021-1, Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska, United States.

    Online Links:

    Other_Citation_Details: 16 p

How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?
    The report and data have been evaluated by DGGS staff for general readability and logical consistency. The accompanying report provides additional discussion of the data collection, processing, and verification methodology.
  2. How accurate are the geographic locations?
    We quantified the horizontal accuracy of the GNSS position data using the latitudinal and longitudinal peak-to-peak errors provided by OPUS.
  3. How accurate are the heights or depths?
    We quantified the vertical accuracy of the GNSS elevation data using the combined error of the ellipsoid height peak-to-peak error provided by OPUS and the vertical uncertainty provided by the National Oceanic and Atmospheric Administration's (NOAA) Vertical Datum Transformation software during conversion from ellipsoid height to ortho height.
  4. Where are the gaps in the data? What is missing?
    This data release is complete.
  5. How consistent are the relationships among the observations, including topology?
    Base station data was processed using NOAA's OPUS static processing service, which derives GNSS coordinates from the average of three independent, single-baseline solutions, each computed by double-differenced carrier-phase measurements from three nearby National Continuously Operating Reference Stations (CORS; table 2). OPUS provides the range of the three individual single baselines, known as the peak-to-peak error. These ranges include any errors from the Continuously Operating Reference Stations (CORS) used during processing. OPUS ortho height ranges are estimated to 95 percent confidence, typically resulting in a much larger potential error compared to the peak-to-peak error of the ellipsoid height. For a more accurate ortho height, we used NOAA's Vertical Datum Transformation software for final elevation conversions. This software employs accurate, multi-parameter mathematical equations and location specific grid models to perform vertical transformations and report the total root-mean-square error.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints:
This report, map, and/or dataset is available directly from the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys (see contact information below).
Use_Constraints:
Any hard copies or published datasets utilizing these datasets shall clearly indicate their source. If the user has modified the data in any way, the user is obligated to describe the types of modifications the user has made. The user specifically agrees not to misrepresent these datasets, nor to imply that changes made by the user were approved by the State of Alaska, Department of Natural Resources, Division of Geological & Geophysical Surveys. The State of Alaska makes no express or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.
  1. Who distributes the data set? (Distributor 1 of 1)
    Alaska Division of Geological & Geophysical Surveys
    Metadata Manager
    3354 College Road
    Fairbanks, AK
    USA

    (907)451-5020 (voice)
    (907)451-5050 (FAX)
    dggspubs@alaska.gov
    Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays
    Contact_Instructions:
    Please view our website (https://www.dggs.alaska.gov) for the latest information on available data. Please contact us using the e-mail address provided above when possible.
  2. What's the catalog number I need to order this data set? RDF 2022-14
  3. What legal disclaimers am I supposed to read?
    The State of Alaska makes no expressed or implied warranties (including warranties for merchantability and fitness) with respect to the character, functions, or capabilities of the electronic data or products or their appropriateness for any user's purposes. In no event will the State of Alaska be liable for any incidental, indirect, special, consequential, or other damages suffered by the user or any other person or entity whether from the use of the electronic services or products or any failure thereof or otherwise. In no event will the State of Alaska's liability to the Requestor or anyone else exceed the fee paid for the electronic service or product.
  4. How can I download or order the data?

Who wrote the metadata?

Dates:
Last modified: 29-Nov-2022
Metadata author:
Alaska Division of Geological & Geophysical Surveys
Attn: Simone Montayne
Metadata Manager
3354 College Road
Fairbanks, AK
USA

(907)451-5020 (voice)
(907)451-5050 (FAX)
dggspubs@alaska.gov
Hours_of_Service: 8 am to 4:30 pm, Monday through Friday, except State holidays
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
Metadata extensions used:

Generated by mp version 2.9.50 on Tue Nov 29 13:11:38 2022