Sound velocity vs. depth plots and CTD cast data collected in April 2021 offshore Santa Cruz, California during USGS field activity 2021-619-FA

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?
   Balster-Gee, Alicia F., Baldwin, Wayne E., and Hart, Patrick E., 20220920, Sound velocity vs. depth plots and CTD cast data collected in April 2021 offshore Santa Cruz, California during USGS field activity 2021-619-FA: data release DOI:10.5066/P9EHITBI, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, California.

   Online Links:

   • https://doi.org/10.5066/P9EHITBI

   This is part of the following larger work.
   Balster-Gee, Alicia F., Baldwin, Wayne E., and Hart, Patrick E., 2022, Calibrated marine sparker source amplitude decay versus offset offshore Santa Cruz, California: data release DOI:10.5066/P9EHITBI, U.S. Geological Survey, Pacific Coastal and Marine Science Center, Santa Cruz, CA.

   Online Links:

   • https://doi.org/10.5066/P9EHITBI

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -122.47431993
   East_Bounding_Coordinate: -121.81507587
   North_Bounding_Coordinate: 37.09648707
   South_Bounding_Coordinate: 36.72920243
   

3. What does it look like?

   2021-619-FA_SVcast_CC1624004_20210426_165412.png (PNG)

   An example sound velocity profile plot image for cast CC1624004_20210426_165412 at the L50A depth site.

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

   Beginning_Date: 19-Apr-2021

   Ending_Date: 28-Apr-2021

   Currentness_Reference:

   ground condition at time data were collected

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

   Geospatial_Data_Presentation_Form: comma-delimited text
   

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. It contains the following vector data types (SDTS terminology):
      • Point (9)
   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: International Equation of State for sea water (EOS-80)
      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?

   2021-619-FA_RVPS_SoundVelCTD_csv.zip

   zip file containing 9 CTD cast csv data files. First 28 rows of each csv file contain information about the cast sample. (Source: Producer defined)

   Pressure (Decibar)

   pressure readings at each sample point measured in decibars. (Source: Producer defined)

   Range of values
   Minimum:	0.15
   Maximum:	66.85334587
   Units:	Decibar
   Resolution:	0.00000001

   Depth (Meter)

   depth readings at each sample point measured in meters below sea level. (Source: Producer defined)

   Range of values
   Minimum:	0.149193091
   Maximum:	66.46995328
   Units:	meters below sea level
   Resolution:	0.00000001

   Temperature (Celsius)

   water temperature readings at each sample point measured in Celsius. (Source: Producer defined)

   Range of values
   Minimum:	9.035969143
   Maximum:	11.13141155
   Units:	celsius
   Resolution:	0.00000001

   Conductivity (MicroSiemens per Centimeter)

   conductivity readings at each sample point measured in MicroSiemens per centimeter. (Source: Producer defined)

   Range of values
   Minimum:	36412.66021
   Maximum:	38231.92969
   Units:	MicroSiemens per centimeter
   Resolution:	0.00001

   Salinity (Practical Salinity Scale)

   salinity readings at each sample point measured in practical salinity scale. (Source: Producer defined)

   Range of values
   Minimum:	33.95811296
   Maximum:	34.2389649
   Units:	Practical Salinity scale
   Resolution:	0.0000001

   Sound Velocity (Meters per Second)

   sound velocity readings at each sample point measured in meters per second. (Source: Producer defined)

   Range of values
   Minimum:	1486.249233
   Maximum:	1492.713653
   Units:	meters per second
   Resolution:	0.000001

   2021-619-FA_RVPS_SoundVelCTD_plots_png.zip

   Zip file containing 9 sound-velocity profile (SVP) plots, one SVP plot per CTD cast location, in PNG format. Speed of sound is plotted as a function of depth. Cast location latitude and longitude and cast date and time are included at the top of each plot. (Source: U.S. Geological Survey)

   2021-619-FA_RVPS_SoundVelCTD_location_shapefile.zip

   zip file contains a shapefile of CTD cast locations and acquisition information (Source: U.S. Geological Survey)

   cast

   Name of velocity profile used to distinguish between casts. (Source: Producer Defined) Unique profile names are automatically generated from the SonTek CastAway CTD instrument. Profile names are in the format: “CC1624004_YYYYMMDD_HHMMSS” where CC1624004 refers to the CTD Device ID, followed by the date stamp in YYYYMMDD format and the UTC timestamp in HHMMSS format.

   castimage

   Name of the Sound Velocity profile plot image. Names are the same as the cast identifier with the .png file extension. (Source: Producer defined.) Unique profile names are automatically generated from the SonTek CastAway CTD instrument. Profile names are in the format: “CC1624004_YYYYMMDD_HHMMSS” where CC1624004 refers to the CTD Device ID, followed by the date stamp in YYYYMMDD format and the UTC timestamp in HHMMSS format.

   Lon

   decimal degree longitude value in WGS 84 (Source: producer defined)

   Range of values
   Minimum:	-122.3334
   Maximum:	-121.9249
   Units:	decimal degrees
   Resolution:	0.0001

   Lat

   decimal degree latitude value in WGS 84 (Source: producer defined)

   Range of values
   Minimum:	36.82796
   Maximum:	36.97551
   Units:	decimal degrees
   Resolution:	0.00001

   utc_dt

   UTC time and date stamp (Source: Producer defined) Date stamp in the format YYYY/MM/DD followed by the UTC time in HH:MM:SS format.

   surveyid

   Unique field activity identifier (Source: U.S Geological Survey) 2021-619-FA is the USGS survey identifier. More info can be found at: https://cmgds.marine.usgs.gov/fan_info.php?fan=2021-619-FA.

   vehicleid

   name of survey vessel (Source: Producer defined) R/V Parke Snavely

   deviceid

   name of CTD device (Source: Producer defined) SonTek CastAway-CTD

   Entity_and_Attribute_Overview:

   The first 28 rows of the csv file contain specific information about the cast. The first column details the information type, and the second column is the value. The first column is listed below:

    %Device
    %File name
    %Cast time (UTC)
    %Cast time (local)
    %Sample type
    %Cast data
    %Location source
    %Default latitude
    %Default altitude
    %Start latitude
    %Start longitude
    %Start altitude
    %Start GPS horizontal error (Meter)
    %Start GPS vertical error (Meter)
    %Start GPS number of satellites
    %End latitude
    %End longitude
    %End altitude
    %End GPS horizontal error (Meter)
    %End GPS vertical error (Meter)
    %End GPS number of satellites
    %Cast duration (Seconds)
    %Samples per second
    %Electronics calibration date
    %Conductivity calibration date
    %Temperature calibration date
    %Pressure calibration date
    (blank)
   

   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)
   • Alicia F. Balster-Gee
   • Wayne E. Baldwin
   • Patrick E. Hart
2. Who also contributed to the data set?
   The authors acknowledge our fellow participants of the sparker testing field activity 2021-619-FA (Pete Dal Ferro, Gerry Hatcher, Jared Kluesner, Rachel Marcuson, Jenny McKee, Dan Powers and Rob Wyland) and our team involved in survey planning and execution (Jackson Currie, William Danforth, Jane Denny, Tim Elfers, Dave Foster, Nathan Miller, Eric Moore and Carolyn Ruppel).
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?
2. How were the data generated, processed, and modified?

   Date: 28-Apr-2021 (process 1 of 4)

   SonTek CastAway-CTD ASCII csv data were downloaded at the end of each field day.

   Date: 04-Mar-2022 (process 2 of 4)

   A Python Jupyter notebook ‘2021-619-FA_CastPlots.ipynb’ was used to read the CTD cast csv data and plot the depth in meters column vs. the speed of sound in meters per second column for each cast site. This python notebook also plotted the csv file name as a title and the date/time stamp and latitude and longitude coordinate info as a text header just below the title.

   Date: 04-Mar-2022 (process 3 of 4)

   Python Jupyter notebook ‘SparkerAndSVcastNavToSQLdb.ipynb’ was used to extract the cast name, cast image (plot) name, longitude, latitude, UTC day/time stamp, Survey identifier (2021-619-FA), vehicle identifier (R/V Parke Snavely), and the device identifier (SonTek CastAway-CTD), and include these information as attributes in a multipoint shapefile named 2021-619-FA_RVPS_SoundVelCTD_location.shp of cast locations.

   Date: 16-May-2023 (process 4 of 4)

   Edits were made to correct spelling in author name. No data were changed. The metadata available from a harvester may supersede metadata bundled within a download file. Users are advised to compare the metadata date of this file to any similar file to ensure they are using the most recent version. (scochran@usgs.gov)

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 SonTek CastAway-CTD conductivity, temperature, and pressure sensors were calibrated in November of 2019. The electronics component arrived calibrated from the manufacturer (https://www.sontek.com/castaway-ctd). This information is contained in the header rows for each cast csv file.
2. How accurate are the geographic locations?
   SonTek CastAway-CTD data has a stated GPS accuracy of 10 meters. Each cast csv file contains the horizontal error (in meters) for the start and end GPS locations in header rows 13 and 19, respectively.
3. How accurate are the heights or depths?
   SonTek CastAway-CTD depth data has a stated accuracy of +/-0.25 percent FS. CSV header rows 14 and 20 have the start GPS vertical error and end GPS vertical error, respectively, in meters for each cast location. Casts were taken at various depths to a maximum of 66 meters, this maximum depth data can be found in Depth column of each csv file.
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?
   All values fall within expected ranges of temperature, specific conductance, and depth. Data have been checked for duplication and omission.

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? Cast data in csv format are contained in the zip file ‘2021-619-FA_RVPS_SoundVelCTD_csv.zip’. A multipoint shapefile of cast locations with cast information included as attributes is provided in the zip file ‘2021-619-FA_RVPS_SoundVelCTD_location_shapefile.zip’. ‘2021-619-FA_RVPS_SoundVelCTD_plots_png.zip’ is a zip file that contains the 9 plotted images of sound velocity (in meters per second) as a function of depth (in meters) for each cast location.
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 the 9 SonTek CastAway csv tables. in format comma-delimited text (version RFC 4180) Size: 0.0832
     Network links:	https://doi.org/10.5066/P9EHITBI

     Data format:	Zip file contains the shapefile of cast location with all pertinent collection information included as attributes. in format Shapefile (version Spatialite 5.0.1) Size: 0.0018
     Network links:	https://doi.org/10.5066/P9EHITBI

     Data format:	Zip file contains the 9 PNG plots of the cast CSV data columns Depth (meters) and Sound Velocity (in meters per second) on the Y and X axes, respectively. in format PNG (version ImageMagick (version 7.0.8-11)) Portable Network Graphic (PNG) Size: 0.4937
     Network links:	https://doi.org/10.5066/P9EHITBI

   • Cost to order the data: None.

5. What hardware or software do I need in order to use the data set?
   CSV data can be viewed with any text editing or spreadsheet software. PNG images can be viewed with any image viewer software. Users must have software capable of reading shapefile (.shp) format to view location point information.

Who wrote the metadata?

Dates:

Last modified: 16-May-2023

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)