Physics-based numerical model simulations of wave propagation over and around theoretical atoll and island morphologies for sea-level rise scenarios

Frequently anticipated questions:

• What does this data set describe?
  1. How might this data set be cited?
  2. What geographic area does the data set cover?
  3. What does it look like?
  4. Does the data set describe conditions during a particular time period?
  5. What is the general form of this data set?
  6. How does the data set represent geographic features?
  7. How does the data set describe geographic features?
• Who produced the data set?
  1. Who are the originators of the data set?
  2. Who also contributed to the data set?
  3. To whom should users address questions about the data?
• Why was the data set created?
• How was the data set created?
  1. From what previous works were the data drawn?
  2. How were the data generated, processed, and modified?
  3. What similar or related data should the user be aware of?
• How reliable are the data; what problems remain in the data set?
  1. How well have the observations been checked?
  2. How accurate are the geographic locations?
  3. How accurate are the heights or depths?
  4. Where are the gaps in the data? What is missing?
  5. How consistent are the relationships among the data, including topology?
• How can someone get a copy of the data set?
  1. Are there legal restrictions on access or use of the data?
  2. Who distributes the data?
  3. What's the catalog number I need to order this data set?
  4. What legal disclaimers am I supposed to read?
  5. How can I download or order the data?
• Who wrote the metadata?

What does this data set describe?

1. How might this data set be cited?
   Shope, James B., and Storlazzi, Curt D., 2019, Physics-based numerical model simulations of wave propagation over and around theoretical atoll and island morphologies for sea-level rise scenarios: data release DOI:10.5066/P9U28JFO, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

   Online Links:

   • https://doi.org/10.5066/P9U28JFO
   • https://www.sciencebase.gov/catalog/item/5be5f849e4b0b3fc5cf8c9ab

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -180.00000000
   East_Bounding_Coordinate: 180.00000000
   North_Bounding_Coordinate: 90.00000000
   South_Bounding_Coordinate: -90.00000000
   

3. What does it look like?
4. Does the data set describe conditions during a particular time period?

   Calendar_Date: 2019

   Currentness_Reference:

   publication date

5. What is the general form of this data set?

   Geospatial_Data_Presentation_Form: netCDF files
   

6. How does the data set represent geographic features?
   1. How are geographic features stored in the data set?
      

      Indirect_Spatial_Reference:

      The model results presented are not for a particular geographic area.

   2. What coordinate system is used to represent geographic features?
      
7. How does the data set describe geographic features?

   Entity_and_Attribute_Overview:

   netCDF files are self-contained and attribute information may be found in the file itself.

   Entity_and_Attribute_Detail_Citation:

   The entity and attribute information was generated by the individual and/or agency identified as the originator of the data set. Please review the rest of the metadata record for additional details and information.

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • James B. Shope
   • Curt D. Storlazzi
2. Who also contributed to the data set?
3. To whom should users address questions about the data?
   U.S. Geological Survey, Pacific Coastal and Marine Science Center

   Attn: PCMSC Science Data Coordinator

   2885 Mission Street

   Santa Cruz, CA
   

   831-427-4747 (voice)

   pcmsc_data@usgs.gov

Why was the data set created?

Low-lying atoll islands are threatened by the effects of climate change, sea-level rise, and wave-driven flooding. Atolls differ widely in their morphologies and other physical characteristics; the wave and water level conditions along these coastlines vary in space and time. These factors make it difficult to project wave-driven alongshore sediment transport changes in accretion and/or deposition along atoll island shorelines under different forcing conditions, especially for future sea-level rise. We generated a number of ideal schematic atoll and atoll island topographies/bathymetries, then used a physics-based numerical wave model and empirical formulations of alongshore sediment transport to project how sea-level rise may alter alongshore sediment transport gradients along atoll island shorelines. The transport gradients were used to evaluate the relative risk of coastal change on atoll islands of differing morphologies due to sea-level rise.

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: 2018 (process 1 of 3)

   The following steps were used in development of the model. For an in-depth discussion of processing, see Shope and Storlazzi (2019). Model results are presented in NetCDF format, accompanied by a README text file that lists the parameters used in each model run. 1. Select a suite of potential morphological parameters that may affect wave-driven sediment transport along atoll islands via literature review. After, testing, these were the atoll diameter, the atoll reef flat depth, the atoll reef flat width, and the atoll island width. Other variables were tested, but were found to have little control on transport patters or were unable to be appropriately modeled at the numerical wave model resolution. 2. Simulate incident wave transformations over the schematic atoll bathymetry using Delft3D-Wave (SWAN). The incident waves were kept constant at 3 m significant wave height, 10 s period, and coming from 0 degrees north. This process was repeated for each different bathymetry and each selected sea-level rise scenario (varying between 0 to +2 m). 3. Extract wave conditions along shore at each model output point nearshore, here defined as the model output point just offshore of a non-inundated model cell. 4. Use the Coastal Engineering Research Center sediment transport formula (e.g., Ashton and Murray, 2006 and Adams et al., 2011) to determine the sediment transport at each alongshore point, defining the alongshore sediment transport gradient. Calculate the divergence of the alongshore sediment transport to determine locations where the shoreline is eroding or accreting. 5. Use a low-pass filter to smooth the inputs into the CERC equation and the Erosion outputs to remove highly local trends that are generated by the model resolution and rectilinear nature. Sum the erosion/accretion values for each shoreline of the atoll island in question (Ocean-facing, lagoon-facing, or the longitudinal ends) to determine the next erosion or accretion for each shoreline type for each island for each morphology and sea-level rise scenario.

   Date: 19-Oct-2020 (process 2 of 3)

   Edited metadata to add keywords section with USGS persistent identifier as theme keyword. No data were changed. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: VeeAnn A. Cross

   Marine Geologist

   384 Woods Hole Road

   Woods Hole, MA
   

   508-548-8700 x2251 (voice)

   508-457-2310 (FAX)

   vatnipp@usgs.gov

   Date: 13-Oct-2021 (process 3 of 3)

   Performed minor edits to the metadata to correct typos. No data were changed. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Susan A. Cochran

   Geologist

   2885 Mission Street

   Santa Cruz, CA
   

   831-460-7545 (voice)

   scochran@usgs.gov

3. What similar or related data should the user be aware of?
   Shope, James B., and Storlazzi, Curt D., 2018, Assessing morphologic controls on atoll island alongshore sediment transport gradients due to future sea-level rise.

   Online Links:

   • https://doi.org/10.3389/fmars.2019.00245

   Other_Citation_Details:

   Shope, J.B., and Storlazzi, C.D., 2019, Assessing morphologic controls on atoll island alongshore sediment transport gradients due to future sea-level rise: Frontiers in Marine Science, doi:10.3389/fmars.2019.00245.

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

1. How well have the observations been checked?
   See Shope and Storlazzi (2019) for an in-depth discussion of accuracy.
2. How accurate are the geographic locations?
   No formal positional accuracy tests were conducted, nor are they applicable.
3. How accurate are the heights or depths?
   No formal positional accuracy tests were conducted, nor are they applicable.
4. Where are the gaps in the data? What is missing?
   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.
5. How consistent are the relationships among the observations, including topology?
   No formal logical accuracy tests were conducted. See Shope and Storlazzi (2019) for additional information.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access_Constraints: None
Use_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 University of California at Santa Cruz and the U.S. Geological Survey as the originators of the dataset and in products derived from these data.

1. Who distributes the data set? (Distributor 1 of 1)
   
   U.S. Geological Survey - ScienceBase

   Denver Federal Center, Building 810, Mail Stop 302

   Denver, CO
   

   1-888-275-8747 (voice)

   sciencebase@usgs.gov
2. What's the catalog number I need to order this data set? Zip file (Atoll_Schematic_NetCDFs.zip) contains output of model simulations in NetCDF format. Please read the accompanying Atoll_Schematic_NetCDFs_README.TXT file, which describes the naming convention and contents of the NetCDF files.
3. What legal disclaimers am I supposed to read?

   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.

4. How can I download or order the data?
   • Availability in digital form:

     Data format:	Zip file contains model data in netCDF format. in format netCDF (version MATLAB R2018b) Size: 1152
     Network links:	https://www.sciencebase.gov/catalog/file/get/5be5f849e4b0b3fc5cf8c9ab?name=Atoll_Schematic_NetCDFs.zip https://doi.org/10.5066/P9U28JFO

     Data format:	text file that describes the accompanying NetCDF files in format text (version TextEdit 1.13) Size: 0.089
     Network links:	https://www.sciencebase.gov/catalog/file/get/5be5f849e4b0b3fc5cf8c9ab?name=Atoll_Schematic_NetCDFs_README.txt https://doi.org/10.5066/P9U28JFO

   • Cost to order the data: None.

Who wrote the metadata?

Dates:

Last modified: 13-Oct-2021

Metadata author:

U.S. Geological Survey, Pacific Coastal and Marine Science Center

Attn: PCMSC Science Data Coordinator

2885 Mission Street

Santa Cruz, CA

831-427-4747 (voice)

pcmsc_data@usgs.gov

Metadata standard:

Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)