An UWB UHF Ice-Penetreating Radar for the Thwaites Melt Project

As a part of the project "Melting at Thwaites grounding zone and its control on sea level" (MELT), we developed a compact 750-MHz ice-penetrating radar for phase-sensitive measurements to infer basal melt and ice layer displacement using multiple passes. The radar operates with 300-MHz bandwidth and a peak output power of 400 W. It is equipped with a small antenna array designed to fit within the limited space underneath the floor of a Twin Otter aircraft (without out-of-mold-line protuberances). The radar was installed and deployed onboard a Twin Otter airplane from the British Antarctic Survey (BAS) as a part of the ongoing International Thwaites Glacier Collaboration (ITGC). We conducted multiple radar survey flights during two consecutive austral summer seasons, collecting ~5 TB of raw data. In this paper, we present an overview of the radar system and antenna implementations. We provide a summary of our field operations and present sample data products to illustrate the instrument capabilities to sound ice as thick as ~1,400 m and map internal reflecting horizons near the grounding line of TG with sub-m vertical resolution. We also discuss the utility of our repeat pass data for inferring ice shelf basal melt rates.