John K. Hall Carolyn D. Ruppel 2019 tabular digital data data release DOI:10.5066/P97EPU2F Woods Hole Coastal and Marine Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Hazards and Resources Program https://doi.org/10.5066/P97EPU2F https://www.sciencebase.gov/catalog/item/5d10eb1ae4b0941bde550208 Carolyn D. Ruppel Deborah R. Hutchinson Arthur H. Lachenbruch John K. Hall 2019 tabular digital data data release DOI:10.5066/P97EPU2F Reston, VA U.S. Geological Survey 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. https://doi.org/10.5066/P97EPU2F https://www.sciencebase.gov/catalog/item/5c65b826e4b0fe48cb390173 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. Lamont Geological Observatory (LGO; now Lamont-Doherty Earth Observatory) and the U.S. Geological Survey, along with other organizations, ran research laboratories on the island during the 1960s and early 1970s as the island drifted in the Amerasian Basin. LGO compiled navigational data, measured gravity and magnetic data, and conducted seismic surveys to image the seafloor. This data release provides the edited LGO-compiled 1 hour navigational data for T-3 from May 1962 until September 1974, along with gravity and magnetic data and calculated anomalies on the same hourly intervals. To provide 1-hour navigational data and some gravity anomaly and magnetic anomaly data for the T-3 ice island circuit of the Amerasian Basin from 1962 to 1974. 19620514 19740915 ground condition Complete None planned -176.792 -73.580 86.330 74.288 USGS Metadata Identifier USGS:5d10eb1ae4b0941bde550208 ISO 19115 Topic Category geoscientificInformation oceans location USGS Thesaurus marine geology navigational data field monitoring stations None U.S. Geological Survey USGS Coastal and Marine Hazards and Resources Program CMHRP Woods Hole Coastal and Marine Science Center WHCMSC Lamont Geological Observatory Lamont-Doherty Earth Observatory marine heat flow T-3 ice island Fletcher's Ice Island navigation magnetic anomaly gravity anomaly None Alpha Ridge Mendeleev Ridge Nautilus Basin Canada Basin Chukchi Plateau Arctic Ocean Amerasian Basin Fletcher's Ice Island T-3 Ice Island Common geographic areas Arctic None. Please see 'Distribution Info' for details. Not to be used for navigation. Users are advised to read the dataset's metadata thoroughly to understand appropriate use and data limitations. Carolyn Ruppel U.S. Geological Survey, Woods Hole Coastal and Marine Science Center Research Geophysicist mailing and physical address

384 Woods Hole Rd.

Woods Hole MA 02543-1598 USA (508) 548-8700 x2339 (508) 457-2310 cruppel@usgs.gov https://www.sciencebase.gov/catalog/file/get/5d10eb1ae4b0941bde550208?name=T3navigationgraphic.jpg T-3 Ice Island navigation track labelled with a selection of dates. The background bathymetry is from: Jakobsson, M. and others (2012), The International Bathymetric Chart of the Arctic Ocean (IBCAO) Version 3.0, Geophys. Res. Lett., 39, L12609, doi:10.1029/2012GL052219. Inset shows the Arctic Ocean and surrounding land masses, with the red box indicating the approximate area corresponding to the larger map. JPEG Original file compiled and processed by Lamont Geological Observatory (now Lamont-Doherty Earth Observatory). Digital data at 1 hour intervals were received in digital form by the U.S. Geological Survey from Dr. John K. Hall (Geological Survey of Israel, retired), who participated in the T-3 expeditions as Lamont staff member during parts of 1966, 1967, and 1968. Microsoft Windows 7 Enterprise edition; Microsoft Excel 2013 Arthur H. Lachenbruch B. Vaughn Marshall C.D Ruppel 2019 Tables in a PDF report 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. data release DOI:10.5066/P91XQ3IS Woods Hole Coastal and Marine Science Center, Woods Hole, MA U.S. Geological Survey, Coastal and Marine Hazards and Resources Program https://doi.org/10.5066/P91XQ3IS https://cmgds.marine.usgs.gov/data/field-activity-data/1963-001-FA/ Kenneth Hunkins Werner Tiemann 1977 Palisades, New York Lamont-Doherty Geological Observatory 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. Ruppel, Carolyn D. Lachenbruch, Arthur H. Hutchinson, Deborah R. Munroe, Robert Mosher, David C. 2019 Journal of Geophysical Research DOI:10.1029/2019JB017587 Washington, D.C. American Geophysical Union The Journal of Geophysical Research article relies on navigational information compiled in this dataset. https://doi.org/10.1029/2019JB017587 Lacking the original data acquired by LGO, no checks for accuracy were possible. Each type of data within the dataset was tested for logical consistency by Carolyn Ruppel. Dates were corrected as needed in the last hours of each year. Where these errors occurred, the original data set received by the U.S. Geological Survey had a date indicator of "0" within January (month 1) for the last few hours of each year due to a presumed error in the interpolation code across year boundaries. The latitudes and longitudes all lie within the Amerasian Basin along a continuous track, as expected. Raw gravity data are of an appropriate and reasonable magnitude, as are the raw magnetic field data. Free air and Bouguer gravity anomalies and magnetic anomalies are also of an appropriate sign and of credible magnitude. complete Background on navigation is summarized in Hunkins and Tiemann (1977)--see cross-reference-- and in the Journal of Geophysical Research report by Ruppel and others (2019) associated with this 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. This text is taken from the report of Hunkins and Tiemann (1977)--see cross-reference: "During the first year [1962] depths were obtained with explosive sources and a geophone detector with a pen-and-ink recorder operated with one channel for the geophone and one for chronometer ticks. In 1963 a Precision Depth Recorder was installed with a 12 kHz Gifft sonar transceiver driving an EDO AN/UQN transducer at a nominal pulsed power of 1000 watts. All soundings were made on a one-second (750 m) sweep with paper fed at approximately 1 cm/hr. The errors of timing and reading are about+ 2 m. These records were digitized at all extrema and slope changes. Corrections for sound velocity conditions in the Arctic Ocean were applied on the basis of Matthew's tables (1939)." The reference for the Matthews tables is: Matthews, D.J., 1939, Tables of the velocity of sound in pure water and sea water for use in echo sounding and sound ranging, Hydrographic Department Report 282 (2nd edition), United Kingdom Hydrographic Department. Hourly navigation for the T-3 Ice Island was determined by LGO by calculating positions between the actual location fixes. Hunkins and Tiemann (1977) report navigation at 12-hour intervals, but more frequent fixes were often available, especially after fixes from Navy satellites became available in 1967. Prior to that time, when navigation relied on the use of theodolites, John K. Hall reports that cloud cover and sun conditions (sun low on horizon in summer) sometimes prevented successful fixes for several days running. The longest period with no navigational fix during the theodolite navigation era was 22 days. The original fixes are no longer available. Hunkins and Tiemann (1977) describe the interpolation procedure between actual navigational fixes: "The interpolated drift track between fixes was constructed on the basis of wind data. Nansen's rule is that ice drifts 30 degrees to the right of the wind and at 1/50th of the wind speed. The ice motion between fixes was determined using speed factors and deviation angles calculated on the basis of the constraints of wind data and a given pair of observed positions. In the event that the computed speed factor exceeds 0.035 (75 percent above Nansen's value) or falls below 0.0075 (37 percent of Nansen's value), the motion is ascribed to both wind drift, using Nansen's constants, and to a steady current whose velocity is determined. This occurs when currents or the effects of winds at a distance cause small movements during periods of calm." Process date is unknown and assigned to 1977 based on date of the Hunkins and Tiemann (1977) report. 1977 Navigation and other data were interpolated to 1 hour intervals by LGO researchers using a Fortran program and a punch card system to enter satellite fixes. No other information is available. Process date is unknown and assigned to 1992 based on the oldest Fortran executable located on a hard drive provided to the U.S. Geological Survey by John K. Hall. 1992 Carolyn Ruppel edited the original text file provided by John K. Hall, fixing incorrect date designators across the yearly boundaries (usually in the last hours of each year), formatting into an Excel file, fixing data columns that were combined into one entry during the conversion to Excel, and adding appropriate headers. The resulting file is the one released here. The native Excel 2013 file was also exported to CSV format using the "save as" command. 2019 Added keywords section with USGS persistent identifier as theme keyword. 20200806 U.S. Geological Survey VeeAnn A. Cross Marine Geologist Mailing and Physical

384 Woods Hole Road

Woods Hole MA 02543-1598 508-548-8700 x2251 508-457-2310 vatnipp@usgs.gov Point 0.001 0.001 Decimal degrees North American Datum of 1927 Clarke 1866 6378206.4 294.978698214 Not known, but likely was water's surface below the ice. 0.1 meters attribute values T3Navigation.xlsx Excel 2013 file (XLSX) containing data. Producer Defined Date Number of day within month at Greenwich meridian. Producer Defined 1 31 date Month Number of month in year at Greenwich meridian. Producer Defined 1 12 Year Last two digits of year of measurement, with year designating the one at the Greenwich meridian. Years are in 20th century. For example, "64" corresponds to 1964. Producer Defined 62 74 year Hour Hour (0 to 23) multiplied by 100 at Greenwich meridian (GMT). For example, 0800 corresponds to 8 in the morning. Producer Defined 0 2300 Latitude North latitude for position Producer Defined 74.288 86.330 Decimal degrees 0.001 Longitude West longitude for position Producer Defined -176.792 -73.580 Decimal degrees 0.001 Azimuth Direction of island's motion; "0" means no azimuth data available Producer Defined 0.1 360.0 degrees 0.1 Water Depth (m) Measured water depth to seafloor beneath the ice (m); "0" means no water depth available Producer Defined 243.8 3893.1 meters 0.1 Total gravity (mgal) Total gravity measurement in milligal. "0.00" means no value. The following was taken from the report of Hunkins and Tiemann (1977; see cross-reference): "Gravity measurements were made several times a day with a Lacoste and Romberg Model G (No. 27) geodetic gravity meter. The meter was mounted on a wooden post which projected through the laboratory floor and was securely frozen into the ice. The meter height was approximately 4 meters above sea level. Ice vibrations generally did not interfere with the observations. In order to record its instrumental drift, this meter was used in comparison measurements at the University of Wisconsin pundulum [sic] station at Barrow, Alaska, 30 times between 1962 and 1970. The base station was located in the furnace room attached to side of the old quonset main building of the Naval Arctic Research Laboratory. The site is marked by a brass disk set in the concrete floor. Abrupt changes in drift occurred in late 1964 and 1969, but these have been accounted for and the data corrected. Elsewhere, a linear drift has been assumed between calibrations." Producer defined 982818.28 983273.59 milligal (10^(-10) m^2/s) 0.01 Free Air anomaly (mgal) To determine the free-air gravity anomaly, Hunkins and Tiemann (1977; see cross-references) state that "the gravity observations were reduced to sea level, and corrected for the acceleration due to east-west motion (Eotvos correction) by the reduction program. This correction seldom exceeded +1 milligal. Maximum errors are considered to be less than 1 milligal for most observations, but possibly as much as +5 milligals during the severest storms." No data valus are represented as 0.00. Producer Defined -68.42 82.66 Bouguer anomaly (mgal) From Hunkins and Tiemann (1977; see cross-reference): "Simple Bouguer anomalies were computed for each observation by adding the attraction of a horizontally infinite plate, of density 1.64 g/cc [1640 kg/m^3] and thickness equal to the water depth, to the free air anomaly." No value denoted as "0.00." Producer Defined 21.71 305.74 Total Magnetic Field (gamma) Total magnetic field in gamma (1 gamma = 1 nanoTesla (nT)). The following is taken from the Hunkins and Tiemann (1977) report (see cross-reference): "The total intensity of the earth's magnetic field was measured almost continuously with a proton precession magnetometer built at the Lamont-Doherty Geological Observatory. Readings were made every six seconds and recorded on a strip chart. Magnetic total intensity was calculated from precession frequency according to the relation H = 23.487386*f where H is the total field in gammas (10^-5 Gauss) and f is the proton precession frequency in Hertz. The precession frequency measurements were made with a frequency counter, whose crystal oscillator time base was checked periodically against other frequency standards. The individual measurements are accurate to better than +/- 10 gammas. Diurnal variations of the earth's magnetic field in polar regions commonly exceed one hundred gammas. The periodic nature of these variations was used to eliminate them by averaging the observations over 24 hour periods. The records were read every hour, and the filtered field strength computed at each observation point by taking an average of the twenty-four hourly readings centered about that time." No value denoted as "0.00." Producer defined 55826.2 58455.0 gamma 0.1 Magnetic Anomaly (gamma) Magnetic anomaly (gammas). The following is taken from the Hunkins and Tiemann (1977) in the cross-reference: "The value of the earth's regional field was removed by the use of a Taylor series expansion of third degree, fitted by least squares to the regional field in this area by the Dominion Observatory of Canada...The area of this investigation lies near the center of their aeromagnetic survey. The magnetic total intensity anomalies presented here are defined as the difference between the observed total magnetic field and the computed regional field at the point of observation." No value denoted as "0.0". The Fortran output file provided by John Hall had no space between this column and the previous one when the values for magnetic anomaly required 6 or more spaces (including the decimal). The file was hand-edited and quality controlled by Carolyn Ruppel to separate these columns, but problems may remain. Producer defined -916.0 1346.1 gammas 0.1 U.S. Geological Survey - ScienceBase mailing and physical address

Denver Federal Center, Building 810, Mail Stop 302

Denver CO 80225 1-888-275-8747 sciencebase@usgs.gov The dataset contains the data in both Excel XLSX format and CSV format (T3navigation.xlsx, T3navigation.csv), browse graphic of data locations (T3navigationgraphic.jpg), and CSDGM metadata in XML, TXT, and HTML formats. 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. XLXS Microsoft Excel version 2013 The dataset contains the XLSX and CSV format of the data, a browse graphic and associated FGDC CSDGM metadata. 21 https://www.sciencebase.gov/catalog/file/get/5d10eb1ae4b0941bde550208 https://www.sciencebase.gov/catalog/item/5d10eb1ae4b0941bde550208 https://doi.org/10.5066/P97EPU2F The first link downloads all the data on the landing page and provides them in a zip file, the second link goes to the dataset landing page where files can be downloaded individually, and the third link goes to the data release main landing page. CSV Microsoft Excel version 2013 Comma-Separated Values exported from Excel The dataset contains the XLSX and CSV format of the data, a browse graphic and associated FGDC CSDGM metadata. 21 https://www.sciencebase.gov/catalog/file/get/5d10eb1ae4b0941bde550208 https://www.sciencebase.gov/catalog/item/5d10eb1ae4b0941bde550208 https://doi.org/10.5066/P97EPU2F The first link downloads all the data on the landing page and provides them in a zip file, the second link goes to the dataset landing page where files can be downloaded individually, and the third link goes to the data release main landing page. None 20240319 U.S. Geological Survey Carolyn D. Ruppel Research Geophysicist mailing and physical address

384 Woods Hole Rd.

Woods Hole MA 02543-1598 508-548-8700 x2339 508-457-2310 whsc_data_contact@usgs.gov The metadata contact email address is a generic address in the event the person is no longer with USGS. (updated on 20240319) Content Standards for Digital Geospatial Metadata FGDC-STD-001-1998