Radar-Derived Internal Structure and Basal Roughness Characterization along a Traverse from Zhongshan Station to Dome A, East Antarctica

Kun Luo,Bo Sun,Xiangbin Cui,Sixin Liu,Xueyuan Tang,Lin Li,Tiantian Wang,Jingxue Guo

doi:10.3390/rs12071079

Abstract

The internal layers of ice sheets from ice-penetrating radar (IPR) investigation preserve critical information about the ice-flow field and englacial conditions. This paper presents a new detailed analysis of spatial distribution characteristics of internal layers and subglacial topography of the East Antarctic ice sheet (EAIS) from Zhongshan Station to Dome A. The radar data of 1244 km along a traverse between Zhongshan Station and Dome A of EAIS were collected during the 29th Chinese National Antarctic Research Expedition (CHINARE 29, 2012/2013). In this study, the Internal Layering Continuity Index (ILCI) and basal roughness were taken as indicators to provide an opportunity to evaluate the past internal environment and dynamics of the ice sheet. Except for the upstream of Lambert Glacier, the fold patterns of internal layers are basically similar to that of the bed topography. The relatively flat basal topography and the decrease of ILCI with increasing depth provide evidence for identifying previous rapid ice flow areas that are unavailable to satellites, especially in the upstream of Lambert Glacier. Continuous internal layers of Dome A, recording the spatial change of past ice accumulation and ice-flow history over 160 ka, almost extend to the bed, with high ILCI and high basal roughness of the corresponding bed topography. There are three kinds of basal roughness patterns along the traverse, that is, “low ξt low η”, “low ξt high η”, and “high ξt high η”, where ξt represents the amplitude of the undulations, and quantifies the vertical variation of the bedrock, and η measures the frequency variation of fluctuations and the horizontal irregularity of the profile. The characteristics of internal layers and basal topography of the traverse between Zhongshan Station and Dome A provide new information for understanding the ancient ice-flow activity and the historical evolution of EAIS.

Highlights

The East Antarctic ice sheet (EAIS) is the world’s largest ice body, and any minor change may cause global sea-level changes
The result of internal layering properties by Internal Layering Continuity Index (ILCI) can be qualitatively seen from the radar profile
Zone D is located at the upstream of the Lambert Glacier region, characterized by a wide valley with deep depression at the bottom (Figure 3d), where most of the bedrock cannot be detected probably due to the scattering and absorption of radar signals

Summary

Introduction

The East Antarctic ice sheet (EAIS) is the world’s largest ice body, and any minor change may cause global sea-level changes. The latest research shows that if climate change maintains its current rate, Totten Glacier, one of the most significant glaciers in East Antarctica, will retreat irreversibly and rapidly in the century This means that EAIS may be much more vulnerable than expected by climate warming, and that its contribution to future global sea-level predictions may be underestimated [1,2]. The lack of understanding of the structure and long-term evolution of EAIS limits the assessment of its potential changes To achieve this goal, it is an effective way to quantify the characteristics of internal structure and basal topography of the ice sheet detected by ice radar [3]. Radar observations can provide information about the ice age [4,5], ice rheology [6,7,8], and ice conditions [9,10,11], and constraints and tests for ice-sheet models [12,13,14], all of which play an irreplaceable role in the assessment of ice sheet mass balance and ice dynamics [15]

Methods

Results

Conclusion