USGS T-3 enhanced thermal data from T-3 Ice Island, 1963-73

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Frequently anticipated questions:

What does this data set describe?

Title: USGS T-3 enhanced thermal data from T-3 Ice Island, 1963-73
Abstract:
The T-3 (Fletcher's) Ice Island in the Arctic Ocean was the site of a scientific research station re-established by the Naval Arctic Research Laboratory starting in 1962. Starting in 1963, the USGS acquired marine heat flow data and coincident sediment cores at sites in Canada Basin, Nautilus Basin, Mendeleev Ridge, and Alpha Ridge as the ice island drifted in the Amerasian Basin. At least 584 heat flow penetrations were attempted, and data were reported at 356 of these. This dataset is the enhanced version of the original data table from Lachenbruch and others (2019; see cross-reference), incorporating additional information such as the probable dates of measurement, physiographic province and surficial geology at each station, and the length of recovered cores. In addition, this dataset converts the original units to SI units and the positions to decimal degrees.
Supplemental_Information:
This dataset is an enhanced version (data converted to modern units; additional information integrated) of Table 2 in: Lachenbruch, A.H., Marshall, B.V., and Ruppel, C.D., 2019, Post-expedition report for USGS T-3 Ice Island heat flow measurements in the High Arctic Ocean, 1963-1973: U.S. Geological Survey data release, https://doi.org/10.5066/P91XQ3IS. (See cross-reference.)
  1. How might this data set be cited?
    Ruppel, Carolyn D., and Lachenbruch, Arthur H., 2019, USGS T-3 enhanced thermal data from T-3 Ice Island, 1963-73: data release DOI:10.5066/P97EPU2F, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    This is part of the following larger work.

    Ruppel, Carolyn D., Hutchinson, Deborah R., Lachenbruch, Arthur H., and Hall, John K., 2019, Thermal Data and Navigation for T-3 (Fletcher's) Ice Island Arctic Ocean Heat Flow Studies, 1963-73: data release DOI:10.5066/P97EPU2F, U.S. Geological Survey, Reston, VA.

    Online Links:

    Other_Citation_Details:
    Ruppel, C.D., Hutchinson, D.R., Lachenbruch, A.H., and Hall, J.K., 2019, Thermal data and navigation for T-3 (Fletcher's) ice island Arctic Ocean heat flow studies, 1963-73: USGS data release, https://doi.org/10.5066/P97EPU2F.
  2. What geographic area does the data set cover?
    West_Bounding_Coordinate: -176.70250
    East_Bounding_Coordinate: -78.75000
    North_Bounding_Coordinate: 86.05683
    South_Bounding_Coordinate: 75.37100
  3. What does it look like?
    https://www.sciencebase.gov/catalog/file/get/5d10eb42e4b0941bde550210?name=T3enhancedheatflowgraphic.jpg (JPEG)
    T-3 heat flow data labelled with the station number and color-coded by heat flow value. The background bathymetry is from: Jakobsson, M. and other (2012), The International Bathymetric Chart of the Arctic Ocean (IBCAO) Version 3.0, Geophys. Res. Lett., 39, L12609, doi:10.1029/2012GL052219.
  4. Does the data set describe conditions during a particular time period?
    Beginning_Date: 1963
    Ending_Date: 1973
    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.
    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 0.001. Longitudes are given to the nearest 0.001. Latitude and longitude values are specified in Decimal degrees. The horizontal datum used is North American Datum of 1927.
      The ellipsoid used is Clarke 1866.
      The semi-major axis of the ellipsoid used is 6378206.4.
      The flattening of the ellipsoid used is 1/294.978698214.
      Vertical_Coordinate_System_Definition:
      Depth_System_Definition:
      Depth_Datum_Name: Not known, but likely was water's surface below the ice.
      Depth_Resolution: 0.1
      Depth_Distance_Units: meters
      Depth_Encoding_Method: attribute values
  7. How does the data set describe geographic features?
    T3EnhancedHeatFlow.xlsx
    Excel 2013 Worksheet (Source: Producer Defined)
    Station
    Heat flow station (ordinal number), usually referred to in T-3 literature as "FL-" then station number. Station numbers are non-sequential where heat flow penetration failed (no data obtained). (Source: Producer Defined)
    Range of values
    Minimum:2
    Maximum:584
    Date
    Probable date of the heat flow measurement in format YYYYMMDD, where YYYY denotes 4 digits for year, MM denotes two digits for month, and DD denotes two digits for day. See process step 4 for information about determination of the date. (Source: Producer Defined)
    Range of values
    Minimum:19630423
    Maximum:19731113
    Date Flag
    Flag indicating the origin of the probable date in the previous column. "c" indicates that the date is from a database of piston cores (University of Wisconsin, 2016--see cross-reference). When a core was not obtained at the heat flow station but the flag is "c", the date could be pinned with certainty due to known dates at adjacent heat flow stations. "g" indicates that the date was derived by merging the positional information with the T-3 navigation file. "i" indicates that the date was inferred based on other information. For station FL-2, the date is consistent with the T-3 navigation track but is several months before FL-3, so may not be correct. The date for FL-476 was inferred based on known dates of cores at adjacent stations. There is a large time gap between FL-476 and FL-483. FL-479 was arbitrarily assigned to 19700101 since no other information about the date could be inferred given the high density of measurements on this part of Alpha Ridge during this period. Refer to process step 4. (Source: Producer Defined) Character set (text).
    Latitude (degree)
    Decimal Degrees of north latitude for heat flow penetration (Source: Producer Defined)
    Range of values
    Minimum:75.371
    Maximum:86.057
    Units:decimal degree
    Resolution:0.001
    Longitude (degree)
    Decimal Degrees of west longitude for heat flow penetration (Source: Producer Defined)
    Range of values
    Minimum:-176.703
    Maximum:-78.750
    Units:decimal degree
    Resolution:0.001
    Water depth (m)
    water depth in meters at location of heat flow penetration, believed to be measured based on wire-out (Source: Producer Defined)
    Range of values
    Minimum:1066
    Maximum:3818
    Units:meters
    Resolution:1
    Physiographic province from Jakobsson
    Physiographic province in which the heat flow station is located based on Jakobsson, M., Hypsometry and volume of the Arctic Ocean and its constituent seas, Geochem. Geophys. Geosyst., 3( 1), doi:10.1029/2001GC000302, 2002. A split was added between Alpha and Mendeleev Ridges and the Greenland-Canada Rise and Slope were combined. Only values of "Alpha Ridge," "Canada Basin," "Mendeleev Ridge," "Nautilus Basin", and "Greenland-Canada Rise/Slope" were used. The submarine highlands within Nautilus Basin were coded as "Nautilus Basin." FL-104 is at the edge of Mendeleev Ridge on the "Chukchi Perched Rise" and is coded as "Mendeleev Ridge." FL-549 and FL-551 are near the boundary with Alpha Ridge polygon and were coded as "Alpha Ridge." FL-550 was coded as "Greenland-Canada Rise/Slope." Refer to process step 4. (Source: Producer Defined) Character set (text).
    Surficial Geology from Boggild
    Surficial seafloor geology at heat flow station from the data in Boggild, K., D. C. Mosher, C. Gebhardt, M. Jakobsson, L. A. Mayer, K. Hogan, and D. Dove (2018), Surficial geology of the Amerasian Basin from subbottom profiler data, Open File Rep. 8465, Geological Survey of Canada, Ottawa, Canada. Refer to process step 4. (Source: Producer Defined) Character set (text).
    Core length (m)
    Length of the piston core recovered during the heat flow penetration from University of Wisconsin NCEI data release (2016) and data provided by Dennis Darby. Values greater than ~3.7 meters indicate overpenetration (weight stand likely buried in the seafloor) of the corer, which had maximum length of 3.66 m. See process step 4. (Source: Producer Defined)
    Range of values
    Minimum:0.76
    Maximum:5.54
    Units:meters
    Resolution:0.01
    1-2 Gradient (milliC/m)
    Thermal gradient in milliCelsius per meter between thermistors 1 and 2, with 1 being the deepest penetrating thermistor. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:24.1
    Maximum:74.5
    Units:milliCelsius per meter
    Resolution:0.1
    1-3 Gradient (milliC/m)
    Thermal gradient in milliCelsius per meter between thermistors 1 and 3, with 1 being the deepest penetrating thermistor. This gradient is used when thermistor 2 is malfunctioning. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:26.4
    Maximum:75.5
    Units:milliCelsius per meter
    Resolution:0.1
    2-3 Gradient (milliC/m)
    Thermal gradient in milliCelsius per meter between thermistors 2 and 3, with 1 being the deepest penetrating thermistor. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:6.9
    Maximum:109.0
    Units:milliCelsius per meter
    Resolution:0.1
    2-4 Gradient (milliC/m)
    Thermal gradient in milliCelsius per meter between thermistors 2 and 4, with 1 being the deepest penetrating thermistor. This gradient is used when thermistor 3 is malfunctioning. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:30.0
    Maximum:62.7
    Units:milliCelsius per meter
    Resolution:0.1
    3-4 Gradient (milliC/m)
    Thermal gradient in milliCelsius per meter between thermistors 3 and 4, with 1 being the deepest penetrating thermistor. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:26.4
    Maximum:104.4
    Units:milliCelsius per meter
    Resolution:0.1
    3-5 Gradient (milliC/m)
    Thermal gradient in milliCelsius per meter between thermistors 3 and 5, with 1 being the deepest penetrating thermistor. This gradient is used when thermistor 4 is malfunctioning. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:34.9
    Maximum:62.9
    Units:milliCelcius per meter
    Resolution:0.1
    4-5 Gradient (milliC/m)
    Thermal gradient in milliCelsius per meter between thermistors 4 and 5, with 1 being the deepest penetrating thermistor. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:47.4
    Maximum:82.9
    Units:milliCelsius per meter
    Resolution:0.1
    1-2 Conductivity (mcal/(cm-s-C))
    Thermal conductivity in millicalorie per (centimeter-second-degree Celsius) measured on the benchtop (not in the sea floor) in the sediment core section recovered between thermistors 1 and 2. Thermistor 1 is the deepest penetrating thermistor. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:1.94
    Maximum:3.60
    Units:millicalorie per (centimeter-second-degree Celsius)
    Resolution:0.01
    1-3 Conductivity (mcal/(cm-s-C))
    Thermal conductivity in millicalorie per (centimeter-second-degree Celsius) measured on the benchtop (not in the seafloor) in the sediment core section recovered between thermistors 1 and 3. Thermistor 1 is the deepest penetrating thermistor. Only used when Thermistor 2 was malfunctioning.(empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:2.37
    Maximum:3.07
    Units:millicalorie per (centimeter-second-degree Celsius)
    Resolution:0.01
    2-3 Conductivity (mcal/(cm-s-C))
    Thermal conductivity in millicalorie per (centimeter-second-degree Celsius) measured on the benchtop (not in the seafloor) in the sediment core section recovered between thermistors 2 and 3. Thermistor 1 is the deepest penetrating thermistor. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:1.58
    Maximum:3.49
    Units:millicalorie per (centimeter-second-degree Celsius)
    Resolution:0.01
    2-4 Conductivity (mcal/(cm-s-C))
    Thermal conductivity in millicalorie per (centimeter-second-degree Celsius) measured on the benchtop (not in the seafloor) in the sediment core section recovered between thermistors 2 and 4. Thermistor 1 is the deepest penetrating thermistor. Column only used when Thermistor 3 was malfunctioning. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:2.14
    Maximum:3.3
    Units:millicalorie per (centimeter-second-degree Celsius)
    Resolution:0.01
    3-4 Conductivity (mcal/(cm-s-C))
    Thermal conductivity in millicalorie per (centimeter-second-degree Celsius) measured on the benchtop (not in the seafloor) in the sediment core section recovered between thermistors 3 and 4. Thermistor 1 is the deepest penetrating thermistor. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:2.13
    Maximum:3.41
    Units:millicalorie per (centimeter-second-degree Celsius)
    Resolution:0.01
    3-5 Conductivity (mcal/(cm-s-C))
    Thermal conductivity in millicalorie per (centimeter-second-degree Celsius) measured on the benchtop (not in the seafloor) in the sediment core section recovered between thermistors 3 and 5. Thermistor 1 is the deepest penetrating thermistor. Column only used when Thermistor 4 was malfunctioning. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:2.79
    Maximum:3.22
    Units:millicalorie per (centimeter-second-degree Celsius)
    Resolution:0.01
    4-5 Conductivity (mcal/(cm-s-C))
    Thermal conductivity in millicalorie per (centimeter-second-degree Celsius) measured on the benchtop (not in the seafloor) in the sediment core section recovered between thermistors 4 and 5. Thermistor 1 is the deepest penetrating thermistor. (empty cell) for no value. (Source: Producer Defined)
    Range of values
    Minimum:2.76
    Maximum:3.56
    Units:millicalorie per (centimeter-second-degree Celsius)
    Resolution:0.01
    Heat flow (HFU)
    Heat flow in heat flow units (HFU) calculated by taking the product of the average thermal gradient and average thermal conductivity; 1 HFU = 41.8 milliWatt/m^2. (Source: Producer Defined)
    Range of values
    Minimum:0.71
    Maximum:2.86
    Units:Heat Flow Units
    Resolution:0.01
    Average % Deviation
    Percentage uncertainty in heat flow measurement (empty cell means no value reported) (Source: Producer Defined)
    Range of values
    Minimum:0.15
    Maximum:39.35
    Units:percentage
    Resolution:0.01
    Maximum Heat Flow Deviation (HFU)
    Maximum uncertainty in heat flow value in heat flow units (HFU). 1 HFU = 41.8 milliWatts/m^2. (Source: Producer Defined)
    ValueDefinition
    empty cellNo average percentage deviation given for heat flow measurement and therefore no absolute value of heat flow deviation
    Range of values
    Minimum:0.01
    Maximum:1.8
    Units:HFU
    Resolution:0.01
    Average thermal gradient (milliC/m)
    Average of interval thermal gradient values reported in columns labelled with thermistor numbers followed by "gradient." (Source: Producer Defined)
    Range of values
    Minimum:26.7
    Maximum:106.7
    Units:milliCelsius per meter
    Resolution:0.1
    Calculated Thermal Conductivity (W/(m-K))
    Average of thermal conductivity values reported in columns labelled thermistor numbers followed by "conductivity," converted to SI units. (Source: Producer Defined)
    Range of values
    Minimum:0.66
    Maximum:1.46
    Units:Watts per (meter-Kelvin)
    Resolution:0.01
    Inferred Thermal Conductivity (W/(m-K))
    Thermal conductivity value determined by dividing the reported heat flow in SI units by the average thermal gradient. (Source: Producer Defined)
    Range of values
    Minimum:0.66
    Maximum:1.89
    Units:Watts per (meter-Kelvin)
    Resolution:0.01
    Heat flow Converted (mW/m^2)
    Conversion of heat flow from heat flow units (HFU) to SI units (mW/m^2) (Source: Producer Defined)
    Range of values
    Minimum:29.7
    Maximum:119.6
    Units:milliWatts per cubic meter
    Resolution:0.1
    Max. Heat Flow Deviation Converted (mW/m^2)
    Maximum uncertainty in heat flow value converted from heat flow units (HFU) to SI units (mW/m^2). 1 HFU = 41.8 milliWatts/m^2. (Source: Producer Defined)
    ValueDefinition
    0.0No absolute maximum heat flow deviation
    Range of values
    Minimum:0.418
    Maximum:75.2
    Units:milliWatts per square meter
    Resolution:0.1
    Uncertainty flag
    Flag indicating whether original dataset provided an uncertainty for this heat flow measurement. "*" indicates none was provided. (Source: Producer Defined) Character set (text).
    Heat Flow Error Bar (mW/m^2)
    Percentage deviation multiplied by heat flow value in SI units. Where no uncertainty is given, an uncertainty of 10% is provided. The resulting error bars are assumed to be both the plus and minus value for each heat flow determination. (Source: Producer Defined)
    Range of values
    Minimum:0.1
    Maximum:27.3
    Units:milliWatts per square meter
    Resolution:0.1

Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)
    • Carolyn D. Ruppel
    • Arthur H. Lachenbruch
  2. Who also contributed to the data set?
    Dataset originally compiled by Lachenbruch et al. (2019)--see cross-reference. This version of the dataset converts original data to modern (SI) units and adds information about date of measurement, length of core obtained at the station, physiographic province, and surface geology.
  3. To whom should users address questions about the data?
    Carolyn Ruppel
    U.S. Geological Survey, Woods Hole Coastal and Marine Science Center
    Research Geophysicist
    384 Woods Hole Rd.
    Woods Hole, MA
    USA

    (508) 548-8700 x2339 (voice)
    (508) 457-2310 (FAX)
    cruppel@usgs.gov

Why was the data set created?

To provide an enhanced version of the T-3 heat flow data with additional information about the heat flow stations and conversions to SI units.

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: 31-Dec-1974 (process 1 of 6)
    This process step gives an overview of the acquisition of the original data. This is copied from details given in this data release in metadata for dataset: "USGS T-3 original thermal gradient, thermal conductivity, and heat flow data from T-3 ice island, 1963-73."
    Details about the operations to acquire the data are given in Lachenbruch and others (2019)--see cross-reference. Summary information about procedures is also provided in the other cross-referenced publications, particularly the Journal of Geophysical Research paper by Ruppel and others (2019). The heat flow measurements were made once a day or once every several days (occasionally two per day) during USGS occupation of the T-3 ice island. The measurements were made through a permanent hole in the ice (moonpool) maintained under the protection of a hut near the Colby Bay portion of the T-3 ice island. The apparatus consisted of a corer with attached thermistors (four thermistors during the first few years of the operation and then five thermistors on a slightly longer core barrel during subsequent years). The thermistor closest to the bottom of the core barrel was designated as #1. Thermistor accuracy was 0.001 degrees Celsius based on Lachenbruch and others(2019).
    The corer with attached thermistors was lowered to the seafloor on a winch system. The probe remained in the bottom sediments long enough for the frictional heat pulse associated with sediment penetration to decay to the conductive part of the curve so that an equilibrium temperature could be determined for each thermistor during post-analysis. Thermal conductivity was not measured in situ in the seafloor. The probe was recovered with sediments in the corer. Far more sediment cores were recovered than heat flow measurements taken (for example, refer to the information in the University of Wisconsin NCEI dataset at https://doi.org/10.7289/v51834g7 for selected information about USGS T-3 sediment cores). It is unknown whether heat flow measurements were not attempted on every coring run or whether the heat flow probe or recording instrumentation suffered frequent problems. The consistent recovery of sediment cores indicates that the probe penetrated the sediments at many locations, meaning that a heat flow measurement was in theory possible at those locations as well.
    After completion of a measurement, data would have been analyzed to determine an equilibrium temperature for each thermistor. These equilibrium temperature data have been lost, as have the bottom water temperature data recorded during the surveys and information about the penetration depth of the probe. For the Journal of Geophysical Research paper by Ruppel and others (2019)--see cross-reference, attempts were made to use the lengths of recovered cores as an indicator of the probe's penetration depth to assist in determination of equilibrium thermal gradients, but this analysis was unsuccessful. The reported data from the heat flow measurements are thermal gradients between adjacent thermistors. For a 4-thermistor penetration with all 4 thermistors operational, the dataset provides thermal gradient values between thermistors 1 and 2, 2 and 3, and 3 and 4. If one thermistor were not functioning (for example, thermistor #2), the reported gradients would be between thermistors 1 and 3 and 3 and 4.
    Thermal conductivity values were measured on the laboratory benchtop on recovered sediment cores using needle probes. The reported values correspond to core sections between each of the working thermistors. For example, if a gradient is reported for the interval between thermistors 2 and 3, then the dataset gives a corresponding thermal conductivity determination in that interval from the corresponding core. The original thermal conductivity data have been lost, but it is suspected that far more thermal conductivity measurements were completed than are compiled or averaged to generate the values in the dataset. Ruppel and others (2019)--see cross-reference-- analyzes some of the thermal conductivity data in this dataset. Heat flow was calculated by multiplying average thermal gradient and average thermal conductivity. Uncertainties are reported on a subset of the values as a percentage of the heat flow. A maximum heat flow uncertainty is also provided by for heat flow values to which a percentage deviation was assigned. Process date likely spanned the duration of the experiment and is reported below as the last day of 1974, which is the approximate date of the USGS report provided in Lachenbruch and others (2019)--see cross-reference Data sources used in this process:
    • Lachenbruch and others (2019)--see cross-reference
    Date: 2019 (process 2 of 6)
    This process step details how the original table was digitized and quality checked. The original table was available only as a PDF scan of Table 2 from Lachenbruch and others (2019). In 2016, Carolyn Ruppel manually keyed most of this table. Subsequently, technical staff (B. Clark and M. Arsenault) at the USGS Woods Hole Coastal and Marine Science Center conducted optical character recognition on parts of the scanned file. The two inputs were combined, and then Deborah Hutchinson conducted quality control on the resulting table. This process identified entries that were partially illegible in the original PDF scan of the report, positions that had been improperly keyed, and one position (station FL-352) that did not plot on the T-3 navigation track obtained through independent means and released with this dataset as "T-3 Ice Island One Hour Navigation: May 14, 1962 to September 15, 1974." Values were corrected in the table based on this analysis. It is expected that some errors likely remain in the transfer of the original PDF scan to the digital data file. It is not believed that any of the possible errors affect the subsequent outcome or analysis in any significant way. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Carolyn Ruppel
    Research Geophysicist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    USA

    508-548-8700 x2263 (voice)
    508-457-2310 (FAX)
    cruppel@usgs.gov
    Date: 2019 (process 3 of 6)
    Original data were averaged, converted, and updated: Latitudes and longitudes were transformed from degree-minute to decimal degree format. Average thermal gradients were determined by averaging reported interval thermal gradients over the number of interval thermal gradients per station. Average thermal conductivity was determined in the same manner using the interval thermal conductivities. Heat flow was converted from Heat Flow Units (HFU) to modern SI units (mW/m^2) by multiplication by the factor of 41.8 mW/m^2 per HFU. The reported maximum deviation of heat flow measurements was similarly converted to HFU. Uncertainties expressed as a percentage were multiplied by the converted (SI units) heat flow to generate an error bar for use in plotting. Where percentage uncertainties were not reported, a value of 10% was adopted to generate the appropriate error bar. The heat flow value was divided by the average gradient to generate an inferred thermal conductivity used by the original reference (Lachenbruch and others, 2019--see cross-reference). Person who carried out this activity:
    U.S. Geological Survey
    Attn: Carolyn Ruppel
    Research Geophysicist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    USA

    508-548-8700 x2263 (voice)
    508-457-2310 (FAX)
    cruppel@usgs.gov
    Date: 2019 (process 4 of 6)
    Using Esri ArcGIS 10.2, the latitude and longitude of the heat flow stations were merged with the Arctic Ocean physiographic province polygons from Jakobsson, M., Hypsometry and volume of the Arctic Ocean and its constituent seas, Geochem. Geophys. Geosyst., 3(1), doi:10.1029/2001GC000302, 2002 and a split added between Alpha and Mendeleev Ridges. The polygon shapefiles were provided by Martin Jakobsson to Carolyn Ruppel. This produced a mapping of physiographic province for each heat flow station. In addition, the positions of the heat flow stations were merged with surficial geology from Boggild, K., D. C. Mosher, C. Gebhardt, M. Jakobsson, L. A. Mayer, K. Hogan, and D. Dove (2018), Surficial geology of the Amerasian Basin from subbottom profiler data, Open File Rep. 8465, Geological Survey of Canada, Ottawa, Canada. The surficial geology GIS was provided to the U.S. Geological Survey by David Mosher, co-author on the cross-referenced Journal of Geophysical Research (Ruppel and others, 2019) paper. Dates were added to the dataset first by using known dates of piston cores retrieved from the Arctic Ocean simultaneously with the acquisition of the heat flow data. The dates are given in the NCEI dataset from University of Wisconsin (2016)--see cross-reference. All successful heat flow stations were presumed to have yielded piston cores since thermal conductivity data are reported for all stations. However, not all the cores may have been sent to University of Wisconsin and are therefore not in the database. When core dates were missing, ArcGIS 10.2 was used to find the date on which the T-3 drift path was closest to a particular heat flow station using the 1-hour navigation provided as part of this release in "T-3 Ice Island One Hour Navigation: May 14, 1962 to September 15, 1974." This method assumes that the position recorded for the heat flow station was where the heat flow was actually measured in the seafloor. However, the position could be recorded when the corer entered the water, and the heat flow station actually recorded when it penetrates the bottom, up to hours later. Also note that this method of merging time-stamped navigation with the positional information for the heat flow data assumes that the heat flow probe entered the seafloor vertically beneath the location of the surface infrastructure on T-3 Ice Island. In modern heat flow measurements, the heat flow probe is only rarely directly beneath the vessel when heat flow is recorded. For stations at which neither method for assigning dates was possible, the date was interpolated based on known dates of preceding/subsequent stations. The lengths of cores recovered at each station were added to the file using information from the University of Wisconsin (2016) NCEI release and from a data file provided by Dr. Dennis Darby of Old Dominion University. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Carolyn Ruppel
    Research Geophysicist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    USA

    508-548-8700 x2263 (voice)
    508-457-2310 (FAX)
    cruppel@usgs.gov
    Date: 21-Jun-2019 (process 5 of 6)
    Text data flags were added as columns in the Excel file to replace color coding used in the working copy of the enhanced data file. Person who carried out this activity:
    U.S. Geological Survey
    Attn: Carolyn Ruppel
    Research Geophysicist
    384 Woods Hole Road
    Woods Hole, Massachusetts
    USA

    508-548-8700 x2263 (voice)
    508-457-2310 (FAX)
    cruppel@usgs.gov
    Data sources used in this process:
    • T3EnhancedHeatFlow.xlsx
    Date: 06-Aug-2020 (process 6 of 6)
    Added keywords section with USGS persistent identifier as theme keyword. Person who carried out this activity:
    U.S. Geological Survey
    Attn: VeeAnn A. Cross
    Marine Geologist
    384 Woods Hole Road
    Woods Hole, MA

    508-548-8700 x2251 (voice)
    508-457-2310 (FAX)
    vatnipp@usgs.gov
  3. What similar or related data should the user be aware of?
    Lachenbruch, Arthur H., Marshall, B. Vaughn, and Ruppel, C.D., 2019, Post-expedition report for USGS T-3 Ice Island heat flow measurements in the High Arctic Ocean, 1963-1973: data release DOI:10.5066/P91XQ3IS, U.S. Geological Survey, Coastal and Marine Hazards and Resources Program, Woods Hole Coastal and Marine Science Center, Woods Hole, MA.

    Online Links:

    Other_Citation_Details:
    This dataset originated as Table 2 in: Lachenbruch, A.H., Marshall, B.V., and Ruppel, C.D., 2019, Post-expedition report for USGS T-3 Ice Island heat flow measurements in the High Arctic Ocean, 1963-1973: U.S. Geological Survey data release, https://doi.org/10.5066/P91XQ3IS.
    Ruppel, Carolyn D., Lachenbruch, Arthur H., Hutchinson, Deborah R., Munroe, Robert, and Mosher, David C., 2019, Heat Flow in the Western Arctic Ocean (Amerasian Basin): Journal of Geophysical Research DOI:10.1029/2019JB017587, American Geophysical Union, Washington, D.C..

    Online Links:

    Other_Citation_Details:
    Ruppel, C.D., Lachenbruch, A.H., Hutchinson, D.R., Munroe, R., and Mosher, D.C., 2019, Heat flow in the Western Arctic Ocean (Amerasian Basin): J. Geophysical Research.
    University of Wisconsin-Madison Department Of Geoscience, 2016, Archive of information about the Ice Island T3 piston core collection: NOAA National Centers for Environmental Information, n/a.

    Online Links:

    Lachenbruch, Arthur H., and Marshall, B. Vaughn, 1966, Heat flow through the Arctic Ocean floor: The Canada Basin-Alpha Rise Boundary: Journal of Geophysical Research vol. 71, issue 4, American Geophysical Union (AGU), Washington, D.C..

    Online Links:

    Other_Citation_Details: pp. 1223– 1248
    University Of Wisconsin-Madison Department Of Geoscience, 2016, Archive of information about the Ice Island T3 piston core collection: NOAA National Centers for Environmental Information, n/a.

    Online Links:

    Lachenbruch, Arthur H., and Marshall, B. Vaughn, 1969, Heat Flow in the Arctic: Arctic Institute of North America, Calgary, Alberta, Canada.

    Online Links:

    • www.jstor.org/stable/40507641

    Other_Citation_Details: pp. 300–311
    Langseth, Marcus G., Lachenbruch, Arthur H., and Marshall, B. Vaughn, 1990, Geothermal observations in the Arctic region: Geological Society of America, Boulder, CO.

    Online Links:

    Other_Citation_Details:
    In: The Arctic Ocean Region, edited by A. Grantz, L. Johnson and J. F. Sweeney, Decade of North American Geology, Vol. L, Geological Society of America, pp. 133-152.

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

  1. How well have the observations been checked?
    This is a legacy dataset collected between 1963 and 1973. To determine accuracy of the original data: Carolyn Ruppel attempted to locate original records at the USGS Menlo Park office and among Arthur Lachenbruch's scientific papers, which are in the possession of Barbara Lachenbruch of Corvalis, Oregon. Lacking the original records (logs, records of heat flow equilibration curves, records of benchtop thermal conductivity measurements), it is impossible to determine whether the derived information reported in this dataset is accurate. The dataset is assumed to be accurate based on material in Lachenbruch and others (2019)--(see cross-reference), which discusses calibrations, internal checks, and other measures taken to ensure that the collected data (geothermal gradients and thermal conductivity values) were of high quality and accuracy. The dataset includes percentage uncertainties on reported heat flow measurements for most of the heat flow stations. It is assumed that these uncertainties are propagated errors from the thermal gradients and thermal conductivities combined. Another accuracy issue concerns the quality of the transfer from the hardcopy table to the digital version. The data were first manually keyed by Carolyn Ruppel in 2016. Subsequently, the data were optically scanned to PDF format and a subset of the data were subjected to optical character recognition by B. Clark and M. Arsenault. The manually keyed and optically-character-recognized data were then quality controlled by Deborah Hutchinson, who made notes about parts of the table that were not legible in the scans and best determinations about the appropriate values. Hutchinson also identified locations that did not confirm to the known T-3 navigation track. The dataset contains JPEG graphics showing the initially digitized table beside the scanned PDF portion of the table, with identified problems marked.
  2. How accurate are the geographic locations?
    Background on navigation is summarized in: Hunkins, K., and W. Tiemann (1977), Geophysical data summary for Fletcher's Ice Island (T-3), 1962-1974, Technical Report, Lamont-Doherty Survey of the World Ocean Rep. CU-1-77, 219 pp, Lamont-Doherty Geological Observatory and in the cross-referenced Journal of Geophysical Research paper associated with this release. See also "T-3 Ice Island One Hour Navigation: May 14, 1962 to September 15, 1974" within this data release. Before 1967, navigation relied on theodolite fixes of the sun (summer) and stars (winter) coupled with a chronometer that was frequently checked for accuracy via radio. Hunkins and Tiemann [1977] estimate a positional error of up to 1 km during the summer and 0.5 km in the winter for this period. Starting in 1967, satellite data from the Navy Navigation Satellite System provided positional fixes, and Hunkins and Tiemann [1977] estimate that positions were known within 250 m. Based on the years of the island's occupation, the horizontal datum is assumed to be NAD27.
  3. How accurate are the heights or depths?
    The water depths reported in the data table accompanying the Lachenbruch and others (2019) report (see cross-reference) are apparently line-out depths for the heat flow apparatus. No additional information with regards to depth measurements is indicated, and no vertical coordinate system is specified. Note that Hunkins and Tiemann (1977) also collected depth measurements using seismic and subbottom profiling systems and these are reported in "T-3 Ice Island One Hour Navigation: May 14, 1962 to September 15, 1974" as part of this data release. It is not known whether these depth measurements were adopted for the heat flow and radiogenic heat datasets.
  4. Where are the gaps in the data? What is missing?
    This file enhances the one released in "USGS T-3 original thermal gradient, thermal conductivity, and heat flow data from T-3 ice island, 1963-73." Refer to metadata for that dataset regarding completeness. In summary, all values present in the original PDF scan were included in that dataset, and a best guess was used when the data were unreadable. This enhanced dataset makes no modifications of the original data in that release and merely adds to that data.
  5. How consistent are the relationships among the observations, including topology?
    Dates are logical based on T-3 navigation track. Positions of measurements were checked to confirm that they lie on the known navigational track for T-1 as provided in this data release as part of the dataset "T-3 Ice Island One Hour Navigation: May 14, 1962 to September 15, 1974." Station FL-532 was correctly digitized but does not lie on the T-1 navigational track. Thermal gradients, thermal conductivity, and heat flow values are all positive and physically plausible. Average calculated thermal conductivity range does not agree with inferred conductivity range, indicating that original dataset may have had access to thermal conductivity data not included in the interval thermal conductivities.

How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?
Access_Constraints: None. Please see 'Distribution Info' for details.
Use_Constraints:
Not to be used for navigation. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations.
  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)
    sciencebase@usgs.gov
  2. What's the catalog number I need to order this data set? The dataset contains the data in both Excel XLSX format and CSV format (T3EnhancedHeatFlowTable.xlsx T3EnhancedHeatFlowTable.csv), browse graphic of data locations (T3enhancedheatflowgraphic.jpg), plotting information (USGST3_RelativeThermalGradientPlots.pdf) and images of the thermal gradients measured at each heat flow station (T3Gradients2_75.jpg, T3Gradients76_192.jpg, T3Gradients196_279.jpg, T3Gradients284_354.jpg, T3Gradients355_427.jpg, T3Gradients429_566.jpg, and T3Gradients567_584.jpg), and CSDGM metadata in XML, TXT, and HTML formats.
  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?

Who wrote the metadata?

Dates:
Last modified: 06-Aug-2020
Metadata author:
Carolyn Ruppel
U.S. Geological Survey, Northeast Region
Research Geophysicist
384 Woods Hole Road
Woods Hole, MA
United States

508-548-8700 x2339 (voice)
cruppel@usgs.gov
Metadata standard:
FGDC Content Standard for Digital Geospatial Metadata (FGDC-STD-001-1998)
This page is <https://cmgds.marine.usgs.gov/catalog/whcmsc/SB_data_release/DR_P97EPU2F/T3_enhancedheatflow.faq.html>
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