Distribution of Shallow Isochronous Layers in East Antarctica Inferred from Frequency-Modulated Continuous-Wave (FMCW) Radar

Abstract

During the 32nd Chinese National Antarctic Research Expedition, the Frequency-Modulated Continuous-Wave (FMCW) radar was used for the first time to obtain the distribution of shallow isochronous layers within the East Antarctic region extending from Zhongshan Station to Kunlun Station. Taking a typical area as a case study, this article describes the complete workflow used in radar data processing, including signal processing and extraction of isochronous layers. The wave velocity model is established according to an empirical formula to calculate the depth of the layer, and the result is compared and corrected with the volcanic record in ice core DT263; the relative error of depth is only approximately 5%. The echograms of the isochronous layers in three regions are presented, including the area around the Dome A, the area 100 km from the Dome A and the area in the Lambert Glacier. A comparison of the echograms within the three regions shows that the isochronous layers are relatively stable in the Dome A and change more intensely in the Lambert Glacier, while the folding of the layer occurs in a concentrated area near Dome A. This folding may be due to the local layer mixing and compression caused by the ice flow and wind-driven processes. The analysis of the distribution of the shallow isochronous layers and age-depth information from different regions provides important data that support the calculation of large-scale accumulation rates and flow history in the Antarctic.