Hydrodynamic timeseries data from south San Francisco Bay, California, summer 2020

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Frequently anticipated questions:

What does this data set describe?

Hydrodynamic timeseries data from south San Francisco Bay, California, summer 2020
Hydrodynamic and sediment transport time-series data, including water depth, velocity, turbidity, suspended particle size, conductivity, and temperature, were collected by the U.S. Geological Survey (USGS) Pacific Coastal and Marine Science Center at two locations in south San Francisco Bay. Data were collected in the channel (one platform) and in the shallows (three co-located platforms) for 2 weeks in July 2020. Data files are grouped by site (channel or shallows). Each site contained instrumentation to collect the data listed, with slight instrument and setup variations between the two sites due to logistics. Users are advised to assess data quality carefully, and to check metadata for instrument information, as platform deployment times and data-processing methods varied.
Additional information about the field activity from which these data were derived is available online at:
Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the U.S. Government.
  1. How might this data set be cited?
    Allen, Rachel M., McGill, Samantha C., Joanne C. T. Ferreira, and Lacy, Jessica R., 20211015, Hydrodynamic timeseries data from south San Francisco Bay, California, summer 2020: data release doi:10.5066/P99Q4CHM, U.S. Geological Survey, Pacific Coastal and Marine Science Center Santa Cruz, California.

    Online Links:

    This is part of the following larger work.

    Allen, Rachel M., McGill, Samantha C., Joanne C. T. Ferreira, Lacy, Jessica R., and Tan, Angela C., 20210301, Hydrodynamic, sediment transport, and sediment flocculation data from south San Francisco Bay, California, summer 2020: data release doi:10.5066/P99Q4CHM, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

    Online Links:

  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -122.1788
    East_Bounding_Coordinate: -122.1669
    North_Bounding_Coordinate: 37.5490
    South_Bounding_Coordinate: 37.5413
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/602a99fad34eb1203113b18a?name=CSF20_SiteMap.jpg&allowOpen=true (JPEG)
    Map of study area showing instrument deployment locations in south San Francisco Bay.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 16-Jul-2020
    Ending_Date: 30-Jul-2020
    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?
      Data were collected continuously at survey locations. 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 1.0E-5. Longitudes are given to the nearest 1.0E-5. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is World Geodetic System 1984 (WGS84).
      The ellipsoid used is WGS84.
      The semi-major axis of the ellipsoid used is 6378137.0.
      The flattening of the ellipsoid used is 1/298.257223563.
  7. How does the data set describe geographic features?
    NetCDF files are self-contained and attribute information may be found in the header of the file itself.
    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)
    • Rachel M. Allen
    • Samantha C. McGill
    • Joanne C. T. Ferreira
    • Jessica R. Lacy
  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)

Why was the data set created?

These data were collected to measure the physical forces that control sediment flocculation, specifically waves, tidal currents, and turbulence, as well as suspended-sediment concentration in the water column. They were collected as part of a San Francisco Estuary Initute (SFEI)-funded study performed collaboratively with the USGS California Water Science Center. These data are intended for science researchers, students, policy makers, and the general public.

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: 16-Jul-2020 (process 1 of 5)
    One platform was deployed in the channel, and it contained the following instruments: Nortek Signature1000 acoustic doppler current profiler, EofE Ultrasonics Altimeter, RBR CTD, Nortek single point acoustic doppler velocimeter with a Seapoint turbidity meter, Sequoia Scientific Laser In-situ scattering and transmissometry (LISST).
    Date: 16-Jul-2020 (process 2 of 5)
    Three platforms were deployed in the shallows, and together contained the following instruments: RDInstrument ADCP, RBR DUO bursting pressure sensor, Nortek single point acoustic doppler velocimeter (no turbidity meter), Sequoia Scientific Laser In-situ scattering and transmissometry (LISST), RBR Virtuoso with Seapoint turbidity meter, EofE Ultrasonics Altimeter, RBR CTD.
    Date: 30-Jul-2020 (process 3 of 5)
    Instruments were retrieved from both the channel and shallows sites. The data from the retrieved instruments were post-processed using manufacturers software packages and USGS matlab codes.
    Date: 01-Mar-2021 (process 4 of 5)
    Data were accumulated into NetCDF files. During post-processing, data collected when instruments were out of the water were removed from the time series. Bad data points identified by 1) the deployment and recovery times, 2) data flagged as erroneous by the manufacturer, 3) amplitude or correlation values outside of predetermined quality thresholds for the velocimeter, were removed. The files include data of intermittent poor quality due to interference by vegetation caught on frames. In a few datasets with persistent vegetative interference the compromised data were removed, as noted in the associated metadata. Turbidity data are raw unless otherwise noted and include high values that may be attributable to vegetation. Use of these data requires careful assessment of data quality. LISST volume concentrations are most accurate when the optical percent transmission is above 30, as light passing through the sample volume is unlikely to be scattered by more than one particle.
    Date: 01-Mar-2021 (process 5 of 5)
    Files were named with a convention that uses a 12- to 15-digit alpha-numeric code. The first three characters for this dataset are all 'CSF' for the experiment name; the fourth and fifth positions represent the calendar year in which the data were collected (20, 2020); the sixth, seventh and eighth characters are an alphanumeric code for the platform name (CHT, SC1, etc.); the ninth and tenth characters represent the instrument position on the platform, where 01 is the top-most. Next is a two- or three-character code for the instrument type (vec, Nortek's Acoustic Doppler Velocimeter; alt, EofE Ultrasonics' altimeter; wh, RDInstrument's acoustic doppler current profile current data; pt, RBR's bursting pressure sensor with temperature; ctd, RBR's CTD; Tu, RBR's Virtuoso turbidity logger; ls, Sequoia Scientific's LISST; sig, Nortek's Signature1000 ADCP). There are an additional 2-4 characters for instruments that collect in a bursting pattern to indicate whether the file includes the raw burst data (-b), the statistics of the burst (-s), or the wave data (-wvs). This indicator is omitted if there is no bursting pattern.
  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?
    No formal attribute accuracy tests were conducted.
  2. How accurate are the geographic locations?
    Horizontal accuracy derived from GPS instrumentation is less than 1 m.
  3. How accurate are the heights or depths?
    There are two sources of uncertainty associated with vertical positioning of the instruments: 1) the measuring tools used during instrument mounting, 2) the amount of settling that occurs during deployment. No corrections were made to the data to account for these errors. Users may refer to the pre-deployment sensor heights provided in the datafiles in addition to the nominal heights of the sensors which are also found in the data files to verify changes in sensor elevation. The heights provided do not account for any sinking that may have occurred during the deployment.
  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. Data fall within expected ranges.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: none
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 originators of the dataset and in products derived from these data. This information is not intended for navigation purposes.
  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)
  2. What's the catalog number I need to order this data set? These data are available in zipped NetCDF format and are accompanied by CSDGM FGDC-compliant metadata.
  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?
  5. What hardware or software do I need in order to use the data set?
    The downloadable data file has been compressed with the "zip" command and can be unzipped with Winzip or other archive utilites. To utilize these data, the user must have software capable of uncompressing the WinZip file and importing and viewing a NetCDF file. These data can be viewed with the NOAA netCDF file viewer, ncBrowse, which can be downloaded from the internet at https://www.pmel.noaa.gov/epic/java/ncBrowse.

Who wrote the metadata?

Last modified: 15-Oct-2021
Metadata author:
PCMSC Science Data Coordinator
U.S. Geological Survey, Pacific Coastal and Marine Science Center
2885 Mission Street
Santa Cruz, CA
United States

831-427-7520 (voice)
Metadata standard:
Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)

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