Radio-echo sounding measurements and ice-core synchronization at Dome C, Antarctica
Anna Winter1, Daniel Steinhage1, Emily J. Arnold2, Donald D. Blankenship3, Marie G. P. Cavitte3, Hugh F. J. Corr4, John D. Paden2, Stefano Urbini5, Duncan A. Young3, and Olaf Eisen1,61Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bremerhaven, Germany 2Center for Remote Sensing of Ice Sheets, Lawrence, KS, USA 3University of Texas Institute for Geophysics, Austin, TX, USA 4British Antarctic Survey, Cambridge, UK 5Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy 6Fachbereich Geowissenschaften, Universität Bremen, Bremen, Germany
Received: 07 Jun 2016 – Accepted for review: 13 Jun 2016 – Discussion started: 14 Jun 2016
Abstract. We present a compilation of radio-echo sounding (RES) measurements of five radar systems (AWI, BAS, CReSIS, INGV and UTIG) around the EPICA Dome C (EDC) drill site, East Antarctica. The aim of our study is to investigate the differences of the various systems in their resolution of internal reflection horizons (IRHs) and bedrock topography, penetration depth, and quality of imaging the basal layer. We address the questions of the compatibility of existing radar data for common interpretation, and the suitability of the individual systems for Oldest Ice reconnaissance surveys. We find that the most distinct IRHs and IRH patterns can be identified and transferred between most data sets. Considerable differences between the RES systems exist in range resolution and depiction of the basal layer. Considering both aspects, which we judge as crucial factors in the search for old ice, the CReSIS and the UTIG systems are the most valuable ones. In addition to the RES data set comparison we calculate a synthetic radar trace from EDC density and conductivity profiles. We identify ten common IRHs in the measured RES data and the synthetic trace. The reflection-causing conductivity sections are determined by sensitivity studies with the synthetic trace. In this way, we accomplish an accurate two-way travel time to depth conversion for the reflectors, without having to use a precise velocity-depth function that would accumulate depth uncertainties with increasing depth. The identified IRHs are assigned with the AICC2012 time scale age. Due to the isochronous character of these conductivity-caused IRHs, they are a means to extend the Dome C age structure by tracing the IRHs along the RES profiles.
Winter, A., Steinhage, D., Arnold, E. J., Blankenship, D. D., Cavitte, M. G. P., Corr, H. F. J., Paden, J. D., Urbini, S., Young, D. A., and Eisen, O.: Radio-echo sounding measurements and ice-core synchronization at Dome C, Antarctica, The Cryosphere Discuss., doi:10.5194/tc-2016-147, in review, 2016.