Temperate Glacier Survey on the Yulong Snow Mountain Using Low-Frequency Ground-Penetrating Radar Data With Fast Coherent Enhancement

Understanding ice thickness distribution and estimating glacier volume are crucial for gaining insights into the dynamics of temperate glaciers. However, comprehensive measurements of these parameters remain limited for the Baishui River Glacier No. 1 (BRG1) on the Yulong Snow Mountain, Lijiang, China. To address this issue, we performed a ground-penetrating radar (GPR) survey on BRG1, employing low-frequency antennas (with center operating frequencies of 25 and 50 MHz, respectively) coupled with a high-voltage transmitter and numerous stacks on the recorded data to enhance the signal-to-noise ratio (SNR). On the glacier surface, we collected common-offset profiles and processed the GPR data using a specified workflow to further improve the SNR. We proposed a fast coherent enhancement (FCE) technique to reduce the effects of clutter scattering and enhance event continuity. Compared with the traditional method, FCE enhanced the processing speed of the 25- and 50-MHz GPR data by approximately $120 \times $ and $50 \times $ , respectively. After data processing, we identified the ice-bedrock interface in the 25-MHz GPR profiles, with ice thicknesses ranging from 40 to 120 m. The survey area was 0.2758 km2, and we calculated the ice volume to be 0.0232 km3 with an average ice thickness of 83 m. By performing GPR numerical simulations and comparing BRG1 with another temperate glacier, we observed that water inclusions substantially contribute to clutter scattering and signal loss in our GPR data. In brief, this study confirms the effectiveness of low-frequency GPR in investigating complex temperate glaciers.