Ice and Bedrock Characteristics Underneath Dome C (Antarctica) From Radio Echo Sounding Data Analysis

Abstract

The Radio Echo Sounding (RES) system is one of the most widely used active remote sensing techniques for polar ice sheet exploration, including bedrock morphology studies and subglacial lake investigations. Recently, bedrock characterization has been improved through the analysis of radar echo strength. The analysis of the RES signal amplitude has been used to highlight areas of high reflectivity variation, attributable to wet ice-bedrock interfaces. In a previous paper the authors described a method to distinguish a wet or dry bedrock-ice interface by analyzing RES data and introducing a linear model for internal ice absorption. In the following paper this subject is reconsidered in greater depth, taking into account important aspects not considered in the previous paper. In particular, a comparison between the ice absorption rate from RES measurements and from EPICA ice core conductivity data was proposed. Moreover, the signal amplitude contributions of internal ice layers and different kinds of rock interface were evaluated. Encouraged by these results, further data analysis produced a new version of the bedrock reflectivity variation map of the Dome C area. The map confirms a wide dispersion of wet/dry rock interfaces in the area studied, indicating the possibility of flowing water along both sides of the Concordia Trench.