Methane and carbon dioxide concentration data, environmental data, and calculations used to determine sea-air flux on the northern Greenland margin

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?
   Boze, Lee-Gray, Thornton, Brett, Pohlman, John W., and Ruppel, Carolyn D., 20241220, Methane and carbon dioxide concentration data, environmental data, and calculations used to determine sea-air flux on the northern Greenland margin: data release DOI:10.5066/P15TMWWP, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

   Online Links:

   • https://doi.org/10.5066/P15TMWWP
   • https://www.sciencebase.gov/catalog/item/669955b7d34e9ac16e164c82

   Other_Citation_Details:

   Boze, L.G., Thornton, B., Pohlman, J.W., and Ruppel, C.D., 2024, Methane and carbon dioxide concentration data, environmental data, and calculations used to determine sea-air flux on the northern Greenland margin: U.S. Geological Survey data release, https://doi.org/10.5066/P15TMWWP

2. What geographic area does the data set cover?

   West_Bounding_Coordinate: -66.5345
   East_Bounding_Coordinate: -50.5381
   North_Bounding_Coordinate: 82.5780
   South_Bounding_Coordinate: 80.7655
   

3. What does it look like?

   https://www.sciencebase.gov/catalog/file/get/669955b7d34e9ac16e164c82?name=oden2019_browsegraphic.jpg&allowOpen=true (JPEG)

   Thumbnail image showing the extent of underway measurements of near-surface and atmospheric methane and carbon dioxide and environmental parameters during the 2019 Ryder cruise during USGS Field Activity 2019-FA-042.

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

   Beginning_Date: 07-Aug-2019

   Ending_Date: 06-Sep-2019

   Currentness_Reference:

   ground condition

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

   Geospatial_Data_Presentation_Form: Tabular Digital Data
   

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 (47310)
   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 0.00001. Longitudes are given to the nearest 0.00001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is World Geodetic System 1984 (WGS 84).
      The ellipsoid used is WGS 84.
      The semi-major axis of the ellipsoid used is 6378137.
      The flattening of the ellipsoid used is 1/298.257.
      

      Vertical_Coordinate_System_Definition:

      Depth_System_Definition:

      Depth_Datum_Name: Mean Sea Level (MSL)
      Depth_Resolution: 0.01
      Depth_Distance_Units: meters
      Depth_Encoding_Method: Attribute values
      

7. How does the data set describe geographic features?

   Attribute Table

   Table containing attribute information associated with the dataset (Source: U.S. Geological Survey)

   polyline_id

   Polyline_id is an integer that identifies a set of continuous data collected along a particular part of the ship’s track during a contiguous time period. The polyline id integers increase sequentially throughout the cruise. The minimum duration for a single polyline is 4 minutes. Intervals shorter than 4 minutes would have only 8-9 evenly spaced time query points at 30 second intervals and were deemed too short for the results to be meaningful, meaning that no polyline was formed from these data. Many polylines are longer than 4 minutes because data acquisition continued for a longer period without interruptions for icebreaking or holding station at one location. (Source: Producer defined)

   Range of values
   Minimum:	1
   Maximum:	126

   seconds

   Seconds elapsed since start of a polyline. (Source: Producer defined)

   Range of values
   Minimum:	30
   Maximum:	81690
   Units:	seconds
   Resolution:	30

   daynumber

   Decimal number representing the day within the year 2019. (Source: Producer defined)

   Range of values
   Minimum:	219.490
   Maximum:	249.491
   Units:	day

   date

   Date of data collection. (Source: Producer defined)

   Range of values
   Minimum:	8/7/2019
   Maximum:	9/6/2019
   Units:	MM/DD/YYYY

   time

   Time of day of data collection. (Source: Producer defined)

   Range of values
   Minimum:	00:00:00
   Maximum:	23:59:30
   Units:	HH:MM:SS

   ship_lat

   30-second interpolated latitude as determined by ship's navigation system. (Source: Producer defined)

   Range of values
   Minimum:	80.76546
   Maximum:	82.57804
   Units:	Decimal degrees north

   ship_long

   30-second interpolated longitude as determined by ship's navigation system (Source: Producer defined)

   Range of values
   Minimum:	-66.5345
   Maximum:	-50.5381
   Units:	Decimal degrees east

   waterdepth

   Water depth as determined by ship's sonar. (Source: Producer defined)

   Value	Definition
   (blank)	30-second interpolated ship's depths were initially recorded as zeros, which were then replaced with blank values.

   Range of values
   Minimum:	46.16
   Maximum:	1650.73
   Units:	meters

   ship_cog

   30-second interpolated ship's course over ground, as determined by ship's navigation system (not used in any calculations). (Source: Producer defined)

   Range of values
   Minimum:	0
   Maximum:	359.9
   Units:	degrees

   ship_sog

   30-second interpolated ship's speed over ground, as determined by ship's navigation system (used to identify polyline_id). (Source: Producer defined)

   Range of values
   Minimum:	.02
   Maximum:	12.45
   Units:	knots

   ship_truewind

   30-second interpolated ship's determination of true wind speed. (Source: Producer defined)

   Range of values
   Minimum:	0
   Maximum:	18
   Units:	meters per second

   ship_trwindir

   30-second interpolated ship's determination of true wind direction (Source: Producer defined)

   Range of values
   Minimum:	0
   Maximum:	360
   Units:	degrees

   baropress

   30-second interpolated barometric pressure measured by ship's meteorological system. (Source: Producer defined)

   Range of values
   Minimum:	996.69
   Maximum:	1023.30
   Units:	millibars

   airT

   30-second interpolated air temperature measured by ship's meteorological system. (Source: Producer defined)

   Range of values
   Minimum:	-4.2
   Maximum:	10.9
   Units:	degrees C

   corrch4wat

   (Calculated) methane concentration in the equilibrator headspace after applying calibration factors to the value measured by the CRDS. (Source: Producer defined)

   Range of values
   Minimum:	1.99
   Maximum:	4.7
   Units:	parts per million (v/v)

   corrco2wat

   (Calculated) carbon dioxide concentration concentration in the equilibrator headspace after applying calibration factors to the value measured by the CRDS. (Source: Producer defined)

   Range of values
   Minimum:	89.09
   Maximum:	434.61
   Units:	parts per million (v/v)

   corrch4air

   (Calculated) methane concentration in air after applying calibration factors to the value measured by the Los Gatos spectrometer. (Source: Producer defined)

   Range of values
   Minimum:	1.93
   Maximum:	2.00
   Units:	parts per million (v/v)

   corrco2air

   (Calculated) carbon dioxide concentration in air after applying calibration factors to the value measured by the Los Gatos spectrometer. (Source: Producer defined)

   Range of values
   Minimum:	396.87
   Maximum:	430.49
   Units:	parts per million (v/v)

   ysiwatT

   30-second interpolated temperature of seawater fed into the laboratory, as measured by the YSI EXO2 sonde (Source: Producer defined)

   Range of values
   Minimum:	-1.45
   Maximum:	8.77
   Units:	degreesC

   ysisal

   30-second interpolated salinity (psu) of seawater fed into the laboratory, as determined by the YSI EXO2 sonde. (Source: Producer defined)

   Range of values
   Minimum:	3.21
   Maximum:	35.34
   Units:	practical salinity units (psu)

   ysipH

   30-second interpolated pH of seawater fed into the laboratory, as determined by the YSI EXO2 sonde (not used in calculations). (Source: Producer defined)

   Range of values
   Minimum:	7.41
   Maximum:	8.47
   Units:	dimensionless

   ysiDO

   30-second interpolated dissolved oxygen (mg/L) in seawater fed into the lab, as measured by the YSI EXO2 sonde (not used in calculations) (Source: Producer defined)

   Range of values
   Minimum:	10.26
   Maximum:	16.52
   Units:	milligram per liter (mg L-1)

   ysifDOM

   30-second interpolated fluorescent dissolved organic matter (fDOM) in seawater fed into the lab, as measured by the YSI EXO2 sonde (not used in calculations) (Source: Producer defined)

   Range of values
   Minimum:	-1.01
   Maximum:	5.42
   Units:	quinine sulfate units (QSU), where 1 QSU = 1 part per billion of quinine sulfate (ppb)

   ysiORP

   30-second interpolated oxidation-reduction potential of seawater fed into the lab, as measured by the YSI EXO2 sonde (not used in calculations). (Source: Producer defined)

   Range of values
   Minimum:	98.29
   Maximum:	193.66
   Units:	millivolts (mV)

   ysiPE

   30-second interpolated phycoerythrin (pigment from cyanobacteria) content of seawater fed into the lab, as measured by the YSI EXO2 sonde (not used in calculations). (Source: Producer defined)

   Range of values
   Minimum:	-1.75
   Maximum:	25.24
   Units:	Relative flourescence units (RFU)

   ysiChl

   30-second interpolated chlorophyll (pigment from phytoplankton) content of seawater fed into the lab, as measured by the YSI EXO2 sonde (not used in calculations) (Source: Producer defined)

   Range of values
   Minimum:	-0.71
   Maximum:	5.57
   Units:	Relative flourescence units (RFU)

   ship_hullwatT

   30-second interpolated temperature of seawater measured with hull-mounted sensor on ship. (Source: Producer defined)

   Range of values
   Minimum:	-1.74
   Maximum:	16.84
   Units:	degrees C

   OstCoeff

   (Calculated) Ostwald coefficient. (Source: Producer defined)

   Range of values
   Minimum:	0.0352871
   Maximum:	0.0562325
   Units:	dimensionless

   ch4_SatAnom

   (Calculated) saturation anomaly (% departure from saturation value) for methane in near-surface waters. (Source: Producer defined)

   Range of values
   Minimum:	2.32
   Maximum:	142.53
   Units:	percentage

   Schmidt_No

   (calculated) Schmidt number (Source: Producer defined)

   Range of values
   Minimum:	1219.92
   Maximum:	2220.97
   Units:	dimensionless

   GasVel_mday

   (calculated) gas transfer velocity (Source: Producer defined)

   Range of values
   Minimum:	0.00001
   Maximum:	10.6778
   Units:	meters per day

   ch4airequil_nM

   (Calculated) concentration of dissolved methane in equilibrium with the measured atmospheric methane concentration. (Source: Producer defined)

   Range of values
   Minimum:	2.92
   Maximum:	4.65
   Units:	nanomolar (nM)

   ch4flux_umolm2day

   (Calculated) sea-air methane flux. (Source: Producer defined)

   Range of values
   Minimum:	0.0001
   Maximum:	44.8295
   Units:	micromole methane per square meter per day

   ch4flux_mgCH4m2day

   (Calculated) sea-air methane flux. (Source: Producer defined)

   Range of values
   Minimum:	0
   Maximum:	0.71727
   Units:	milligrams methane per square meter per day

   ch4flux_mgCm2day

   (calculated) sea-air flux of methane (mg CH4-C m-2 d-1) (Source: Producer defined)

   Range of values
   Minimum:	0
   Maximum:	0.5371
   Units:	milligrams methane carbon per square meter per day

   WaterConc_ch4nM

   (Calculated) concentration of methane in near-surface seawater. (Source: Producer defined)

   Range of values
   Minimum:	3.21050
   Maximum:	11.33201
   Units:	nanomoles methane per liter water

   Ko_co2

   (Calculated) carbon dioxide solubility coefficient. (Source: Producer defined)

   Range of values
   Minimum:	.04691
   Maximum:	.07672
   Units:	dimensionless

   gastransCO2

   (Calculated) sea-air gas transfer coefficient for carbon dioxide. (Source: Producer defined)

   Range of values
   Minimum:	0.00126
   Maximum:	126.93193
   Units:	dimensionless

   co2flux_mmolm2day

   (Calculated) sea-air flux of carbon dioxide (mmol m-2 d-1). (Source: Producer defined)

   Range of values
   Minimum:	-700.25
   Maximum:	4.33
   Units:	millimoles of carbon dioxide per square meter per day

   co2flux_mgCO2m2day

   (Calculated) sea-air flux of carbon dioxide (mg CO2 m-2 d-1). (Source: Producer defined)

   Range of values
   Minimum:	-30818.14132
   Maximum:	190.61811
   Units:	milligrams of carbon dioxide per square meter per day

   co2flux_mgCO2Cm2day

   (Calculated) sea-air flux of carbon dioxide carbon(mg CO2-C m-2 d-1). (Source: Producer defined)

   Range of values
   Minimum:	-8410.74064
   Maximum:	52.02259
   Units:	milligrams of carbon dioxide carbon per square meter per day

Who produced the data set?

1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
   • Lee-Gray Boze
   • Brett Thornton
   • John W. Pohlman
   • Carolyn D. Ruppel
2. Who also contributed to the data set?
   These data were acquired during USGS field activity 2019-FA-042, which was part of the 2019 Ryder expedition on the icebreaker (I/B) Oden. USGS data acquisition was partially sponsored by the U.S. Department of Energy (DOE) through USGS-DOE interagency agreement DE-FE0023495. The Swedish Polar Secretariat, the Center for Coastal and Ocean Mapping at University of New Hampshire, and Stockholm University funded the cruise and provided access to ship's navigational and sensor data for this data release. The National Science Foundation provided in-kind transportation and accommodations for USGS shipboard scientist Lee-Gray Boze through the Arctic Support Program.
3. To whom should users address questions about the data?
   U.S. Geological Survey, Woods Hole Coastal and Marine Science Center

   Attn: Lee-Gray Boze

   Physical Scientist

   384 Woods Hole Rd

   Woods Hole, MA
   

   USA

   508-548-8700 x2266 (voice)

   lboze@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: 2022 (process 1 of 4)

   The following text is partially taken and then modified from the Supporting Information for Pohlman and others, 2017 (see cross-reference). The navigational data, meteorological parameters, water environmental parameters, and gas concentrations were collected by different instruments and correlated based on time stamping or acquisition of the data on a single computer with a program that provides a single, continuous time stamp based on a Network Time Protocol (NTP). Navigational data (latitude and longitude) and meteorological data (true wind speed) were recorded from IB Oden digital log files; instrument data were recorded at intervals ranging from three to seven seconds, conditional upon the data latency of the Picarro CRDS data stream. The ship's position is determined using global positioning system (GPS) receivers.
   The ship's meteorological sensors are located on top of the bridge. Because the standard method for determining sea-air flux depends on the square of the windspeed, small oscillations or quality problems in the true windspeed data are magnified by the flux calculation. Near-surface water temperature and salinity were measured with a YSI EXO2 sonde in a flow-through chamber using water pumped into the ship's laboratory. The chamber was located upstream of the equilibrator that forms the front-end to the USGS Gas Analysis System (USGS-GAS), which consisted of a G-2301f CRDS that received headspace gas from a Weiss-type equilibrator.
   The shipboard laboratory component of the surface water analysis element of the USGS Gas Analysis System consists of a seawater feed, a YSI EXO2 sonde, a Weiss-type equilibrator, a single-channel air-handler and a Picarro G-2301f CRDS. The intake of the seawater pump was located 3 meters below the waterline of the bow. Based on the characteristics of the shipboard plumbing and a pumping rate of 20 liters of seawater per minute to the wet lab, the water samples required time to traverse the distance between the pump intake at the bow and equilibrator in the shipboard laboratory. A split of the water pumped through the tubing from the seawater intake was directed to the YSI EXO2 sonde, which measured water temperature, salinity, and other parameters (e.g., pH, dissolved oxygen and fDOM). A second split of the flow sprayed into the equilibrator. Gas in the equilibrator was circulated continuously at a rate of 2 liters per minute through the single-channel air-handler, where it was dried and a fraction (80 milliliters per minute) fed continuously through the G-2301f. At the beginning of the expedition and prior to initiating the key surveys, the leak rate of the closed-loop gas analysis system that includes the Picarro G-2301f CRDS was measured. Tests were conducted by injecting 50 milliliters of a 1000 part per million methane certified gas standard into the 1.5 liter analytical loop with the equilibrator sealed at the base. The change in methane concentration over time (i.e., the leak rate) was then monitored. The much greater first order turnover time based on the measured leak rate means that system leakage did not meaningfully affect the methane concentrations measured in the equilibrator during this expedition.
   Concentrations of methane and carbon dioxide were measured with a Picarro G-2301f CRDS for near-surface water and the Los Gatos direct absorption spectrometer for air in the atmospheric marine boundary layer. The Los Gatos direct absorption spectrometer was operated by Brett Thornton of Stockholm University. Concentrations are determined from the 12C absorption spectrum for those species. The measured concentration of methane and carbon dioxide for the Los Gatos instrument and the G-2301f, as appropriate, were corrected using a slope and offset correction based on a linear best-fit regression between the measured values and standards of known concentration. The slopes and offsets for the concentration calibration were determined from Air Liquide certified gas standards that contained 1.21, 2.01 and 30 parts per million methane, and 198, 348 and 500 parts per million carbon dioxide (± 5%). Concentration standards were analyzed at least once per day during the expedition.
   Processing took place between 2019 and 2022. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Lee-Gray Boze

   Physical Scientist

   384 Woods Hole

   Woods Hole, MA
   

   USA

   508-548-8700 x2266 (voice)

   508-457-2310 (FAX)

   lboze@usgs.gov

   Date: 2022 (process 2 of 4)

   Data files created by the LabVIEW program were divided into sections of maximum length of one day, with additional smaller sections corresponding to continuous records between operational and calibration interruptions. The data were processed using Excel_2018 to filter out bad data, using the following thresholds: Beginning on day 3 of the expedition (08/10/2019), when the vessel slowed to less than 1 knot, data were not recorded from the CRDS, sonde, or Los Gatos spectrometer. Records with non-physical YSI sonde values were removed. Non-physical YSI measurements were those outside the following ranges: Salinity between 0 and 35 (consistent with Stranne and others, 2021); Temperature between -2 and 10 C (consistent with Stranne and others, 2021); DO between 0 and 17 (DO values outside this range are not environmentally reasonable); pH between 7 and 9 (pH outside this range is considered not physically possible); fDOM between -5 and 20 (values outside this range are beyond the sensor's calibration and not considered physically plausible for oceans); ORP between 0 and 250 (values outside the range are not physically possible for the oceans); Chlorophyll between 0 and 20 (values outside this range are not physically possible for the ocean). In addition, water depths recorded as 0 meters were removed and left as empty cells. Missing YSI values were interpolated from values collected one minute before and prior. In 6 instances, there were no data available to perform the interpolation. Those records (6 out of 47317) were deleted. Processing took place from 2019 to 2022. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Lee-Gray Boze

   Physical Scientist

   Woods Hole Coastal and Marine Science Center

   Woods Hole, MA
   

   USA

   508-548-8700 x2266 (voice)

   508-457-2310 (FAX)

   lboze@usgs.gov

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

   The data resulting from the Excel processing were read into Matlab (version 2021A). The data for each continuous period were linearly interpolated at 30 second intervals. The 30-second interpolation was done on discrete time snippets of data (polylines) split up into segments during which data were being collected between icebreaking or other activities. The interpolated data were written to spreadsheets using Matlab. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Carolyn Ruppel

   Research Geophysicist

   Woods Hole Coastal and Marine Science Center

   Woods Hole, MA
   

   USA

   508-548-8700 x2339 (voice)

   508-457-2310 (FAX)

   cruppel@usgs.gov

   Date: 17-May-2023 (process 4 of 4)

   In Excel 365, the interpolated data that had been written to the spreadsheet in the previous process step were used to calculate point-by-point intermediate and final values related to gas saturations in near-surface waters, sea-air fluxes of carbon dioxide and methane, and other parameters. The details of the calculations are given in the Supporting Information for Pohlman and others (2017), which documented operations on similar data for the West Spitsbergen margin.
   YSI EXO2 sonde temperature and salinity were used to determine (a) Bunsen solubility coefficients used to calculate dissolved gas concentrations from headspace measurements made by the CRDS and (b) the Schmidt number used to calculate gas fluxes. In previous data releases (Ruppel and others, 2017), surface water temperatures from the ship’s hull-mounted temperature sensor were used to calculate these parameters. The hull-mounted temperatures could not be used for the calculations for this data release because the values exceeded the known range of surface water temperatures present during the survey.
   The data were exported as a CSV file. Person who carried out this activity:
   

   U.S. Geological Survey

   Attn: Lee-Gray Boze

   Physical Scientist

   Woods Hole Coastal and Marine Science Center

   Woods Hole, MA
   

   USA

   508-548-8700 x2266 (voice)

   508-457-2310 (FAX)

   lboze@usgs.gov

3. What similar or related data should the user be aware of?
   Jakobsson, Martin, Mayer, Larry A., Nilsson, Johan, Stranne, Christian, Calder, Brian, O'Regan, Matthew, Farrell, John W., Cronin, Thomas M., Bruchert, Volker, Chawarksi, Julek, Eriksson, Bjorn, Fredriksson, Jonas, Gemery, Laura, Glueder, Anna, Holmes, Felicity A., Jerram, Kevin, Kirchner, Nina, Mix, Alan, Muchowski, Julia, Prakash, Abhay, Reilly, Brendan, Thornton, Brett, Ulfsbo, Adam, Weidner, Elizabeth, Akesson, Henning, Handl, Tamara, Stahl, Emelie, Boze, Lee-Gray, Reed, Sam, West, Gabriel, and Padman, June, 2020, Ryder glacier in northwest Greenland is shielded from warm Atlantic water by a bathymetric sill: Communications Earth and Environment 1, Article number 45, Springer Nature, London.

   Online Links:

   • https://doi.org/10.1038/s43247-020-00043-0

   Pohlman, John W., Greinert, Jens, Ruppel, Carolyn, Silyakova, Anna, Vielstadte, Lisa, Casso, Michael, Mienert, Jurgen, and Bunz, Stefan, 2017, Enhanced CO2 uptake at a shallow Arctic Ocean seep field overwhelms the positive warming potential of emitted methane: Proceedings of the National Academy of Sciences of the United States doi:10.1073/pnas.1618926114.

   Online Links:

   • https://doi.org/10.1073/pnas.1618926114

   Ruppel, Carolyn, Pohlman, John W., and Casso, Michael, 2017, Data and calculations to support the study of the sea-air flux of methane and carbon dioxide on the West Spitsbergen margin in June 2014: data release DOI:10.5066/F7M906V0, U.S. Geological Survey, Reston, VA.

   Online Links:

   • https://doi.org/10.5066/F7M906V0

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

1. How well have the observations been checked?
   All data and calculated values are within physically reasonable ranges. Sources of inaccuracies in the cleaned data set can include: bad satellite fixes for ship's navigation and high water content remaining in the headspace gas stream injected into the Picarro G-2301f CRDS for CH4 and CO2 concentrations (columns ch4watlo, ch4wathi, co2wat in data file). Sources of inaccuracies in the cleaned data set can also include values out of calibration for the YSO EXO2 sonde (e.g., columns ysipH, ysiDO, ysifDOM, ysiORP, ysiPE, and ysiChl in the data file). Interpolating data at 30 s intervals can also introduce artifacts. The ship's hull-mounted temperature sensor (column hullwatT) had accuracy of +/- 0.002 degrees Celsius and a resolution of 0.0001 degrees Celsius. The sonde (YSI EXO2) parameters have the following accuracy and resolution based on the owner's manual: salinity (column ysisal), measured in practical salinity units, converted from electrical conductivity internally in the sonde using Standard Method 2520 (www.standardmethods.org): accuracy 1% of conductivity measured in milliSiemens per centimeter and resolution 0.01 milliSiemens per centimeter; water temperature (column ysiwatT), accuracy +/- 0.01 degrees Celsius and resolution 0.00 degrees Celsius; pH (column ysipH), accuracy +/- 0.2 and resolution 0.01; dissolved oxygen (column ysiDO), measured optically, accuracy +/- 0.1 milligrams per liter and resolution 0.01 milligrams per liter; dissolved organic matter (column ysifDOM), accuracy not applicable and resolution of 0.01 quinine sulfate units (QSU); oxidation-reduction potential (column ysiORP), accuracy not applicable and resolution of 0.01 millivolts; phycoerythrin (column ysiPE), accuracy not applicable and resolution of 0.01 relative fluorescence units (RFU); chlorophyll (column ysiChl), accuracy not applicable and resolution of 0.01 relative fluorescence units (RFU). The accuracy of gas concentrations measured by the Picarro G-2301f CRDS was determined empirically based on 13 analyses of certified gas standards for methane and carbon dioxide. For the Picarro G-2301f CRDS, the methane and carbon dioxide concentrations have accuracy of +/- 0.01 parts per million and +/- 0.7 parts per million, respectively. The water vapor determination has accuracy of 0.004%.
2. How accurate are the geographic locations?
   Horizontal accuracy of global positioning system used by the IB Oden is not known, but is expected to be within 10 m. As documented in Ruppel and others (2017), the estimated maximum horizontal inaccuracy that could be introduced by interpolating recorded positions at 30 second time intervals is 30 to 75 meters for ship's speed over ground of 4 to 10 knots, respectively.
3. How accurate are the heights or depths?
   The Marinsat Skipper GDS101 echosounder used for water depth measurements on the IB Oden has accuracy of ~1% of water depth, or ~0.5 m to 16.5 m for the range of water depths recorded here. The intake for the water used to measure gas concentrations is 7-8 m below the waterline. Thus, the vertical accuracy (water depth) is generally within 5 to 10 m for most of the dataset.
4. Where are the gaps in the data? What is missing?
   Because data were removed during periods of icebreaking or CRDS calibration, shiptracks and times are non-continuous in the data set. Otherwise, the data set is considered complete for the information collected, as described in the abstract and logical consistency report. Users are advised to read the rest of the metadata carefully for additional details.
5. How consistent are the relationships among the observations, including topology?
   Time gaps are present throughout the data set. Time gaps are related to periods when the Picarro G-2301f CRDS was undergoing calibration or the ship's speed over ground was less than one knot (e.g., during icebreaking). During icebreaking, the flow of seawater through the supply system was too contaminated with ice or air to accurately represent near-surface waters. In limited instances, missing values for seawater salinity and seawater temperature (mostly from the YSI EXO2) were interpolated using data from adjacent time intervals. For other YSI EXO2 parameters, missing data were replaced by no data values (999.0) and not included in the interpolation algorithm.

How can someone get a copy of the data set?

1. Who distributes the data set? (Distributor 1 of 1)
   
   GS ScienceBase

   U.S. Geological Survey

   Denver Federal Center, Building 810, Mail Stop 302

   Denver, CO
   

   United States

   1-888-275-8747 (voice)

   sciencebase@usgs.gov
2. What's the catalog number I need to order this data set? The dataset includes the data in CSV format (Greenland2019_InterpolatedData_Release.csv), browse graphic (oden2019_browsegraphic.jpg) and CSDGM 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 for other purposes, nor on all computer systems, 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:	CSV file of the data, browse graphic, and CSDGM metadata. in format comma-separated values (CSV) (version Excel 365 and LabVIEW 2018) Size: 12.3
     Network links:	https://www.sciencebase.gov/catalog/file/get/669955b7d34e9ac16e164c82 https://doi.org/10.5066/P15TMWWP

   • Cost to order the data: None

Who wrote the metadata?

Dates:

Last modified: 20-Dec-2024

Metadata author:

U.S. Geological Survey, Northeast Region

Attn: Lee-Gray Boze

Physical Scientist

384 Woods Hole Road

Woods Hole, MA

US

508-548-8700 x2266 (voice)

508-457-2310 (FAX)

whsc_data_contact@usgs.gov

Contact_Instructions:

The metadata contact email address is a generic address in the event the person is no longer with USGS.

Metadata standard:

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