Data Publications

Dome Fuji, Antarctica Core DF2 1-cm AC-ECM Data

  • Japanese Antarctic Research Expedition
  • 2015
  • Dome Fuji, Antarctica Core DF2 1-cm AC-ECM Data
  • A20180613-012
  • ice core
  • physical properties
  • Core_Length: 3035 m
  • Dome Fuji
  • Fujita, S., Parrenin, F., Severi, M., Motoyama, H., and Wolff, E. W.: Volcanic synchronization of Dome Fuji and Dome C Antarctic deep ice cores over the past 216 kyr, Clim. Past, 11, 1395-1416,, 2015.
  • Dome Fuji, Antarctica Ice Core DF2 1 cm AC-ECM Data at -20C, for depth range 975 - 2200m. The climatic record from the 2nd Dome Fuji (Antarctica) deep ice core was analyzed using AC-ECM (AC electrical conductivity measurements). AC-ECM is a method to detect the complex admittance between electrodes dragged on the ice surface with mm-scale resolution and uses 1V and 1MHz. Methods are as follows. After equilibrating for 1 day at the cold-roomtemperature at Dome F, all core sections, which were 93mm in diameter and about 1.5 m long, were cut parallel to their central axes. The cut surfaces were further finished with a microtome knife to make fresh, smooth surfaces. Immediately after a surface was cut and finished, two AC-ECM electrodes were dragged along the surface with a 1 MHz frequency, 1 V signal. The AC-ECM electrodes were automatically dragged along the ice with 2mm step using a moter module. Although the signal was sampled every 2mm, we provide only 10mm running averages of the data to remove noise. The AC-ECM system consists of two coaxial electrodes and an auto-balance bridge (HP model 4284A precision LCR meter). It measures the complex admittance Y= G+Bi, where G is the conductance and B is the susceptance, at the surface of ice using 1MHz to detect the high-frequency limit conductance of ice; here high-frequency limit means frequency well above the Debye dispersion only, and below the dispersions that exist above the microwave region. The electrodes were aligned perpendicular to the core axis and 15mm apart. The effective resolution of the electrodes approximately equaled the distance between the electrodes (15mm); based on a physical principle that the electrical field decreases inversely proportional to the distance from a given location to each electrode. Within this distance, about 65% of the lines of electrical force cross. In earlier studies, the AC loss factor (loss tangent) was given as a result of the AC-ECM. It was G/B, conductance divided by susceptance. The loss factor is proportional to the concentration of sulfuric acid and hydrogen ions. In this set of data, we provide our results as conductance G. In 2015, Fujita, Parrenin et al. (2015) volcanically synchronized two deep ice cores, Dome Fuji (DF) and EPICA Dome C (EDC), drilled at remote dome summits in Antarctica, to improve our understanding of their chronologies. For their study, AC-ECM data of the DF2 core were used from a limited depth range 975-2200m. Here, we open these data to the public. The data have two information of the depth. The first column is the depth of the DF2 core. The third column is the DF2 depths converted into equivalent depths of the DF core. The second column is the conductance (nS) between the electrodes. Note that, in this version of the data, no actions for noise cleaning were done. Except the averaging for every 10mm, data is still a kind of raw data.
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