Nearshore wave time-series: ERA5 hindcast period 1979-2023 - U.S. Canada border to Bering Strait (ver. 2.0, November 2024)

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?
   Engelstad, Anita, Erikson, Li H., Reguero, Borja G., Gibbs, Ann E., and Nederhoff, Kees, 20241127, Nearshore wave time-series: ERA5 hindcast period 1979-2023 - U.S. Canada border to Bering Strait (ver. 2.0, November 2024): data release DOI: 10.5066/P931CSO9, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

   Online Links:

   • https://doi.org/10.5066/P931CSO9

   This is part of the following larger work.
   Engelstad, Anita, Erikson, Li H., Reguero, Borja G., Gibbs, Ann E., and Nederhoff, Kees, 2024, Nearshore wave time-series along the coast of Alaska computed with a numerical wave model(ver. 2.0, November 2024): data release DOI: 10.5066/P931CSO9, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

   Online Links:

   • https://doi.org/10.5066/P931CSO9

   Other_Citation_Details:

   Suggested Citation: Engelstad, A.C., Erikson, L.H., Reguero, B.G., Gibbs, A.E., Nederhoff, K.M., 2024, Nearshore wave time-series along the coast of Alaska computed with a numerical wave model (ver. 2.0, November 2024): U.S. Geological Survey data release, https://doi.org/10.5066/P931CSO9.

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -168.14470
   East_Bounding_Coordinate: -140.99484
   North_Bounding_Coordinate: 71.39871
   South_Bounding_Coordinate: 63.19128
   

3. What does it look like?

   WaveTimeSeries_LocationOverview.jpg (jpg)

   Satellite image showing the coastline for which wave time series are available. Also shown are the subdivisions used for file packaging.

4. Does the data set describe conditions during a particular time period?

   Beginning_Date: 01-Jan-1979

   Ending_Date: 31-Dec-2023

   Currentness_Reference:

   time period for which the data were modeled

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:

      Time-series data are available along the Alaska coast. Refer to self-contained NetCDF files for more location information.

   2. What coordinate system is used to represent geographic features?
      Horizontal positions are specified in geographic coordinates, that is, latitude and longitude. Latitudes are given to the nearest 0.0001. Longitudes are given to the nearest 0.0001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.
      

      Vertical_Coordinate_System_Definition:

      Altitude_System_Definition:

      Altitude_Datum_Name:

      approximate Mean Sea Level as determined by the Prudhoe NOAA tide station

      Altitude_Resolution: 0.01
      Altitude_Distance_Units: meters
      Altitude_Encoding_Method:

      Explicit elevation coordinate included with horizontal coordinates

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 header of the file itself. Attributes are latitude, longitude and depth for each location, as well as significant wave heights (Hs), mean wave period Tm (Tm0,-1), mean wave period Tm01 (Tm0,1)and mean wave direction(Dm) for the 1979-2019. Additionally, flags advise caution where necessary when using the data. Flag_D is used for time steps when the wave and/or wind directions at the model boundary differ by more than 15 degrees between the ERA5 hindcast data and the value determined from the downscaled wave database (DWDB). 20 degrees is maximum difference that wind and wave directions are allowed to differ, otherwise the timestep is set to NaN. Flag_S indicates possible inconsistencies between adjacent time series locations, caused by either the use of different offshore ERA5 hindcast locations in the alongshore directions, or by a switch from one numerical model domain to another. Additionally, values for which the difference in Hs is greater than 0.15 m are flagged to inform the user of this difference. Flags are set for differences greater than 0.20 m (Flag_Hs020), 0.25 m (Flag_Hs025), 0.50 m (Flag_Hs050), 0.75 m (Flag_Hs075) and 1 m (Flag_Hs100). For all flags, 1 indicates this condition is true and 0 that it is not true. Transect IDs are associated with each location and are named in the following scheme: [A1A2A3_N1_N2], where [A1A2A3_N1_N2] is a unique ID for each transects that corresponds to the wave parameter output in the file. A1 is an identifier for the type of transect exposure (E for exposed transects, or S, sheltered, describing transects along Bays and Lagoons). A2 can be either E (east), C (central), or W (west), describing the general location in A3, which is abbreviated by either B (Beaufort Sea) or C (Chukchi Sea). N1 is a numerical baseline ID, and N2 the numerical transect order, starting from the Canada border. For files which include ‘BeringStrait_to_NortonSound’ in their file name, the ID consists only of [A1_N1_N2] where A1 is NSD. File names reflect the geographic area and the isobath for which the files contain data. For example, WaveTimeSeries_ERA5_KotzebueSound_to_BeringStrait_10mDepth.nc contains data for locations from Kotzebue Sound to the Bering Strait (also see browse graphic) along the 10 m isobath. Note that not every transect necessarily contains unique wave data. Due to the grid resolution, transects might share an output location.

   Entity_and_Attribute_Detail_Citation: U.S. Geological Survey
   

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Anita Engelstad
   • Li H. Erikson
   • Borja G. Reguero
   • Ann E. Gibbs
   • Kees Nederhoff
2. Who also contributed to the data set?
   We thank Dr. Babak Tehranirad (Stantec Inc.) and Kevin de Bruijn (TU Delft, The Netherlands) for review of the wave data.
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?

How was the data set created?

1. From what previous works were the data drawn?

   ERA5 (source 1 of 2)

   Copernicus Climate Change Service, 2017, ERA5: Fifth generation of ECMWF atmospheric reanalyses of the global climate: Copernicus Climate Change Service Climate Data Store, online.

   Online Links:

   • https://cds.climate.copernicus.eu/cdsapp#!/home

   Type_of_Source_Media: online database
   Source_Contribution: reanalyzed atmospheric, land and oceanic climate variables
   

   IBCAO (source 2 of 2)

   IBCAO Version 4.0 Compilation Group, 2020, The International Bathymetric Chart of the Arctic Ocean (IBCAO) Version 4.0.: British Oceanographic Data Centre, National Oceanography Centre, NERC, UK, online.

   Online Links:

   • https://www.gebco.net/data_and_products/gridded_bathymetry_data/arctic_ocean/

   Type_of_Source_Media: online database
   Source_Contribution:

   gridded continuous terrain model covering land and ocean in the Arctic region

2. How were the data generated, processed, and modified?

   Date: 30-Jun-2020 (process 1 of 4)

   Obtained topobathymetric elevation data and generated grid bathymetries for wave simulations. Data sources used in this process:

   • IBCAO

   Date: 15-Aug-2020 (process 2 of 4)

   Generated reduced input for wave simulations using methods outlined in the accompanying summary of methods (Engelstad and others, 2024) and in Reguero and others, 2013 and Camus and others, 2014. Data sources used in this process:

   • ERA5

   Date: 01-May-2021 (process 3 of 4)

   Tested wave simulations with Simulating Waves Nearshore (SWAN; Booij and others, 1999) for all grids. This included model validation with observations where available and initial QC checks. Developed look-up table routine for time series. Simulated waves for all domains. Reconstructed time series for ERA5 wave time series and wrote out time series in the nearshore. The mean wave period Tm01 was calculated from Tm using an empirical relationship (quadratic fit). For additional information see Engelstad and others, 2024.

   Date: 30-Jul-2024 (process 4 of 4)

   v2.0: Simulated waves for two additional domains and reconstructed time series (BeringStrait_NortonSound_10mDepth.nc and BeringStrait_NortonSound_5mDepth.nc). While for the previous domains, the output locations on the 5 and 10 m isobath for each transect ID was chosen to be on the closest grid point to the isobaths from the ocean side transect end, for these domains, the output locations were chosen to be the closest grid point when extending the transect out to the 5 m or 10 m isobath. Wrote out time series to the end of 2023 for all domains. Changed Bounding Coordinates values, corrected typos in metadata file. Changed data type for flags to int16 to save space.

3. What similar or related data should the user be aware of?
   Booij, Nico, Ris, Roeland, and Holthuijsen, Leo, 2021, The effect of changing sea ice on nearshore wave climate trends along Alaska’s central Beaufort Sea coast.

   Online Links:

   • https://doi.org/10.1029/98jc02622

   Other_Citation_Details:

   Booij, N., Ris, R. C., and Holthuijsen, L. H., 1999, A third-generation wave model for coastal regions. I- Model description and validation: Journal of Geophysical Research, v. 104, p. 7649–7666.

   Camus, Paula, Menéndez, Melisa, Méndez, Fernando J., Izaguirre, Cristina, Espejo, Antonio, Cánovas, Verónica, Pérez, Jorge, Rueda, Ana, Losada, Inigo J., and Medina, Raúl, 2014, A weather-type statistical downscaling framework for ocean wave climate.

   Online Links:

   • https://doi.org/10.1002/2014JC010141

   Other_Citation_Details:

   Camus, P., Menéndez, M., Méndez, F.J.,Izaguirre, C., Espejo, A., Cánovas, V., Pérez, J., Rueda, A., Losada, I.J. and Medina, R., 2014, A weather-type statistical downscaling framework for ocean wave climate: Journal of Geophysical Research: Oceans, v. 119, p. 7389-7405.

   Engelstad, Anita C, Erikson, Li H, Reguero, Borja G, Gibbs, Ann E, and Nederhoff, Kees, 2024, Database and Time Series of Nearshore Waves Along the Alaskan Coast from the United States-Canada Border to the Bering Sea.

   Online Links:

   • https://doi.org/10.3133/ofr20231094

   Other_Citation_Details:

   Engelstad, A.C., Erikson, L.H., Reguero, B.G., Gibbs, A.E., and Nederhoff, K., 2024, Database and time series of nearshore waves along the Alaskan coast from the United States-Canada border to the Bering Sea: U.S. Geological Survey Open-File Report 2023–1094, 23 p., https://doi.org/10.3133/ofr20231094.

   Falgout, J.T., Gordon, J., Williams, B., and Davis, M.J., 2024, USGS Advanced Research Computing, USGS Denali Supercomputer..

   Online Links:

   • https://doi.org/10.5066/P9PSW367

   Other_Citation_Details:

   Falgout, J.T., Gordon J., Williams B., Davis M. J., USGS Advanced Research Computing, USGS Denali Supercomputer: U.S. Geological Survey, https://doi.org/10.5066/P9PSW367

   Reguero, Borja, Méndez, Fernando, and Losada, Iñigo, 2013, Variability of multivariate wave climate in Latin America and the Caribbean.

   Online Links:

   • https://doi.org/10.1016/j.gloplacha.2012.09.005.

   Other_Citation_Details:

   Reguero, B.G., Méndez, F.J., and Losada, I.J., 2013, Variability of multivariate wave climate in Latin America and the Caribbean: Global and Planetary Change, v. 100, p. 70-84.

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

1. How well have the observations been checked?
   The Simulating Waves Nearshore (SWAN) model and the look-up table method used to generate this data set have been validated with observations. Significant wave heights (Hs) are modeled with a combined root mean square error (RMSE) of 0.18 m for several locations. Flags were added to the data to advise the user of caution where necessary when using the data. Flag_D is used for time steps when the wave and/or wind directions at the model boundary differ by more than 15 degrees between the ERA5 hindcast data and the value determined from the downscaled wave database (DWDB). 20 degrees is maximum difference that wind and wave directions are allowed to differ, otherwise the timestep is set to NaN. Flag_S indicates possible inconsistencies between adjacent time series locations, caused by either the use of different offshore ERA5 hindcast locations in the alongshore directions, or by a switch from one numerical model domain to another. Additionally, values for which the difference in wave height is greater than 0.15 m are flagged to inform the user of this difference. Flags are set for differences greater than 0.20 m, 0.25 m, 0.50 m, 0.75 m and 1 m. For all flags, 1 indicates this condition is true and 0 that it is not true.
2. How accurate are the geographic locations?
   Data are concurrent with topobathymetric DEM locations. A formal accuracy assessment of the horizontal positional information in the data set has not been conducted.
3. How accurate are the heights or depths?
   A formal accuracy assessment of the vertical positional information in the data set has not been conducted.
4. Where are the gaps in the data? What is missing?
   Dataset is considered complete for the information presented, as described in the abstract.
5. How consistent are the relationships among the observations, including topology?
   Data have undergone quality checks and meet standards. Missing data have been filled with -9999 values. Missing data are caused by sea-ice coverage. For some locations, especially in the Beaufort Sea, data for entire years might be missing.

How can someone get a copy of the data set?

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

   2885 Mission Street

   Santa Cruz, CA
   

   831-427-4747 (voice)

   pcmsc_data@usgs.gov
2. What's the catalog number I need to order this data set? These data are available in six netCDF files Files are organized by three regions (U.S. Canada border to Nuwuk (Point Barrow), Nuwuk to Kotzebue Sound, Kotzebue Sound to Bering Strait), near two isobaths (5m and 10m depth) which is reflected in the file name (for example, WaveTimeSeries_ERA5_US_CanadaBorder_to_Nuwuk_10mDepth.nc)
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:	File contains hindcast time series data for the Beaufort Sea from the U.S. Canada border to Nuwuk (Point Barrow) at the 5 m isobath. in format netCDF Size: 7600
     Network links:	https://doi.org/10.5066/P931CSO9

     Data format:	File contains hindcast time series data for the Beaufort Sea from the U.S. Canada border to Nuwuk (Point Barrow) at the 10 m isobath. in format netCDF Size: 7600
     Network links:	https://doi.org/10.5066/P931CSO9

     Data format:	File contains hindcast time series data for the Chukchi Sea from Nuwuk (Point Barrow) to Kotzebue Sound at the 5 m isobath. in format netCDF Size: 8500
     Network links:	https://doi.org/10.5066/P931CSO9

     Data format:	File contains hindcast time series data for the Chukchi Sea from Nuwuk (Point Barrow) to Kotzebue Sound at the 10 m isobath. in format netCDF Size: 8500
     Network links:	https://doi.org/10.5066/P931CSO9

     Data format:	File contains hindcast time series data for the Chukchi Sea from Kotzebue Sound to the Bering Strait at the 5 m isobath. in format netCDF Size: 4400
     Network links:	https://doi.org/10.5066/P931CSO9

     Data format:	File contains hindcast time series data for the Chukchi Sea from Kotzebue Sound to the Bering Strait at the 10 m isobath. in format netCDF Size: 4400
     Network links:	https://doi.org/10.5066/P931CSO9

     Data format:	File contains hindcast time series data for the Chukchi Sea from the Bering Strait through Norton Sound at the 5 m isobath. in format netCDF Size: 6600
     Network links:	https://doi.org/10.5066/P931CSO9

     Data format:	File contains hindcast time series data for the Chukchi Sea from the Bering Strait through Norton Sound at the 10 m isobath. in format netCDF Size: 5800
     Network links:	https://doi.org/10.5066/P931CSO9

   • Cost to order the data: None.

5. What hardware or software do I need in order to use the data set?
   These data can be viewed with any software that reads netCDF files, such as Mathworks MATLAB™, Python, Panoply.

Who wrote the metadata?

Dates:

Last modified: 27-Nov-2024

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)