Preliminary exploration of the interior structure of the Amery ice shelf, East Antarctica

摘要

During China Antarctic Expedition in 2002-2003, to investigate the interior structure of the Amery Ice Shelf (AIS), East Antarctica, we performed ground-penetrating radar (GPR) survey at seven designed locations across the AIS. GPR data can be used to determine precisely the thickness of shallow snow accumulation layer, and the depth and morphology of meteoric-sea ice boundary (between meteoric water ice layer and seawater layer). GPR profiles obtained at some designed locations can reflect the seawater penetrating lines in unconsolidated refreezing sea ice layer under the AIS. So, based on the GPR data we can estimate the thickness of the refreezing sea ice layer under the AIS at these locations, which is meaningful for studying the mass balance of the AIS. The reflections in GPR profiles from meteoric-sea ice boundary at different locations possess noticeably different dynamic characteristics, which reflect the difference in the structure of sea ice layer under different parts of the AIS. This structural difference of the sea ice layer under different parts of AIS may be resulted from the difference of basal freezing and desalinating processes of seawater. The basic characteristics of ocean circulation and the distribution of freezing and melting under the AIS can be determined by analyzing GPR profiles in different runs.