Ground Penetrating Radar and Glaciological methods: Firn structure and density measurements in the accumulation area of the Grosser Aletschgletscher winter-2024

The study of firn structure and density in the accumulation area of the Grosser Aletschgletscher was carried out using Ground Penetrating Radar (GPR) as a Geophysical technique and snow-pit, snowcore, and firncore as glaciological methods. Here we provide the 1.8 km-long GPR transect data acquired on 29 February 2024 on the Ewigschneefeld. We used an IDS monostatic, 200 and 600 MHz dual-frequency, shielded GPR system. This measurement provides detailed information on firn stratigraphy along the spatial scale. The provided data here also has a GPS track of the long GPR profile. The GPR settings can be found in the corresponding files named "GPR_LongProfile" extensions. The Common Mid-Point method (CMP) data was gathered at three locations of the accumulation area of the Grosser Aletschgletscher. We used a Pulse-Ekko mono-static 500 MHz GPR system, consisting of a separate shielded transmitter and receive antenna. The CMP gathering is a method of acquiring the GPR data by keeping the constant distance between the transmitter and receiver antenna and moving them in a horizontal direction with a constant offset (more regarding the CMP data acquisition, refer to Patil et al, 2025). The file names as CMP2, CMP3, and CMP4 refer to the acquired CMP data at the Mönchsjoch, Ewigschneefeld, and Jungfraufirn areas of the Grosser Aletschgletscher, respectively. The CMP data helps to quantify the firn density profiles through the radar wave velocity analysis. Glaciological methods: We measured direct density observations using a 4 m deep snow pit at the Ewigschneefeld on 29 February 2024. We measured the snow density using a 17 cm long metallic cylinder of approximately 4.75 cm in diameter, which resulted in a vertical resolution of 17 cm. We also gathered 3.8 m deep firncore from the bottom of the 4 m deep snowpit. A shallow snowcore of 5.8 m was obtained using the "Mark II Ice Coring System” from Kovacs Ice Drilling Equipment with a diameter of 9 cm. A similar snowcore of 5.4 m long was obtained on the Mönchsjoch plateau on 2 March 2024. For any assistance with the data reading, contact Akash Patil.