Time-series measurements of pressure, conductivity, temperature, and water level collected in Puget Sound and Bellingham Bay, Washington, USA, 2018 to 2021

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?
   Nowacki, Daniel J., Stevens, Andrew W., vanArendonk, Nathan R., and Grossman, Eric E., 20211211, Time-series measurements of pressure, conductivity, temperature, and water level collected in Puget Sound and Bellingham Bay, Washington, USA, 2018 to 2021: data release DOI:10.5066/P9JTFJ6M, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

   Online Links:

   • https://doi.org/10.5066/P9JTFJ6M

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -123.1410499
   East_Bounding_Coordinate: -122.3846892
   North_Bounding_Coordinate: 48.762701
   South_Bounding_Coordinate: 47.0512439
   

3. What does it look like?

   oak_harbor_pswl.jpg (JPEG)

   Photo of stilling well containing water-level sensor deployed at Oak Harbor, Washington

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

   Beginning_Date: 02-Nov-2018

   Ending_Date: 04-Jun-2021

   Currentness_Reference:

   ground condition at time data were collected

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:

      Data were collected continuously at each sensor. 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 0.000001. Longitudes are given to the nearest 0.000001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is D_WGS_1984.
      The ellipsoid used is WGS_1984.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257224.
      

      Vertical_Coordinate_System_Definition:

      Altitude_System_Definition:

      Altitude_Datum_Name: North American Vertical Datum of 1988
      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?

   Entity_and_Attribute_Overview:

   NetCDF files are self-contained and attribute information may be found in the header of 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)
   • Daniel J. Nowacki
   • Andrew W. Stevens
   • Nathan R. vanArendonk
   • Eric E. Grossman
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?

These water-level data were collected in support of Puget Sound - Coastal Storm Modeling System (PS-CoSMoS), a numerical modeling system to predict coastal flooding and coastal change impacts associated with sea-level rise, storms, and river flooding driven by change in climate and land use. In part, the observations are used to calibrate and validate water levels simulated by PS-CoSMoS.

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: 04-Jun-2021 (process 1 of 3)

   Beginning on November 2, 2018, In-Situ Aqua TROLL 200 sensors were deployed at seven locations, typically piers, around Puget Sound and Bellingham Bay. The sensors were suspended within 2-inch PVC stilling wells attached to pier pilings. All parameters were measured at 15-minute intervals during the deployments, except for during periodic servicing trips or when the instruments were not recording because of sensor failure or battery depletion. For most files, each 15-minute measurement is a burst-average of 60 measurements collected at 1 Hz. For Olympia deployment B an average of 10 samples was used. For Hoodsport deployment B a single sample per 15-minute interval was recorded. Specifics are given in the metadata of the netCDF files. Recording ceased on June 4, 2021.

   Date: 14-Sep-2021 (process 2 of 3)

   Upon initial sensor deployment at each location, a survey marker was established and at least three one-minute occupations using a GNSS system were performed to establish the marker elevation. During subsequent servicing trips, the marker was again occupied with the GNSS system to determine any potential vertical motion of the pier or surrounding area. Tape-down measurements from the survey marker to the water surface were made along with pressure, conductivity, and temperature reported by the instrument to relate the recorded parameters to water-surface elevation relative to a known vertical datum. The resulting offset was applied to the recorded data to produce the reported time-series of water-surface elevation. The offsets are given in the metadata of the netCDF files. Variability in the marker elevation and tape-down measurements was used to estimate the uncertainty in the reported water-surface elevation.

   Date: 10-Nov-2021 (process 3 of 3)

   Data downloaded from the instruments were ingested using the xarray Python package. Data quality assurance and quality control was performed by inspecting all variables and removing spurious values. Details of which portions of data were flagged and removed are available in the netCDF metadata. Attributes conforming to CF (Climate and Forecast) Conventions version 1.6 were added and the dataset was serialized to netCDF. All times are in Coordinated Universal Time (UTC). Filenames are named using the convention xxxYtroll-a.nc, where “xxx” is the first three letters of the site name, and “Y” is a letter (A through D) corresponding to the sequential deployment at each location.

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?
   The specified accuracy of the In-Situ Aqua TROLL 200 is (conductivity): ± 0.5 percent of reading + 1 μS/cm when reading less than 80,000 μS/cm, ± 1.0 percent of reading when reading above 80,000 μS/cm; (pressure): ±0.05 percent FS from -5 to 50 degrees C; (temperature): ±0.1 degrees C.
2. How accurate are the geographic locations?
   A formal accuracy assessment of the horizontal positional information in the data set has not been completed.
3. How accurate are the heights or depths?
   The elevations of the sensors were determined using a combination of Global Navigation Satellite Systems (GNSS) surveys and tape-down measurements. Upon initial sensor deployment at each location, a survey marker was established and at least three one-minute GNSS occupations were performed to establish the marker elevation. The GNSS positions were post-processed with Trimble Business Center software to apply differential corrections from a nearby GNSS continuously operating reference station operated by the Washington State Reference Network (WSRN; http://www.wsrn3.org/) relative to the North American Datum of 1983 (2011 realization) reference frame. Orthometric elevations relative to the NAVD88 vertical datum were computed using offsets from the National Geodetic Survey Geoid12B geoid model. Once the positions of the survey markers were established, synchronous observations of the vertical distance between the survey marker and water surface elevation using a tape measure and depth measurements from the in-situ sensors were used to determine the elevations of the sensors. An estimate of the accuracy of the offset used to convert depth to water-surface elevation relative to NAVD88 was computed by propagating the combined uncertainties in a) the elevation of the survey marker as determined from repeat GNSS occupations, b) the sum of the tape-down measurements (measurements from the survey marker to the water surface) and the computed height of the water column above the pressure sensor as determined from repeat measurements. The maximum uncertainty in the offset across all sites is estimated to be 0.033 m. Uncertainties for each site are included in the metadata of each netCDF file. This uncertainty does not explicitly include instrument accuracy as described in the Attribute Accuracy Report above.
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.

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 the U.S. Geological Survey as the originator(s) of the dataset and in products derived from these data.

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? Downloadable data in netCDF format. NetCDF files are named by site location code and deployment sequence at each site.
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:	Time-series data in netCDF format following Climate and Forecast (CF) Metadata Conventions version 1.6. File download sizes range from 104.4 kB to 2.8 MB. in format NetCDF (version netCDF-4, CF-1.6) Size: 2.8
     Network links:	https://doi.org/10.5066/P9JTFJ6M

   • 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 capable of reading netCDF files.

Who wrote the metadata?

Dates:

Last modified: 11-Dec-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)