Bed diagnosis in the Dome Fuji region, East Antarctica, using airborneradar data and englacial attenuation estimates

• Main Authors: Matsuoka, Kenichi, Van Liefferinge, Brice, Binder, Tobias, Eisen, Olaf, Helm, Veit, Karlsson, Nanna, Pattyn, Frank, Steinhage, Daniel
• Format: Conference Object
• Language: unknown
• Published: 2019
• Subjects: Antarctic; Austral; Dome Fuji; East Antarctica; The Antarctic; Antarc*; Antarctica; Ice Sheet
• Online Access: https://epic.awi.de/id/eprint/49585/; https://epic.awi.de/id/eprint/49585/1/EGU2019-11263-1.pdf; https://hdl.handle.net/10013/epic.d440bb01-0132-4e98-9a0e-24b0446da2ed; https://hdl.handle.net/

Radar reflectivity of the ice-sheet bed has been used as a diagnostic measure of the basal conditions. Such bed diagnosis could lead to constrain magnitude and spatial pattern of geothermal flux which remains poorly known under the Antarctic Ice Sheet. Radar reflectivity can be estimated from the radar-observed bed returned power by extracting englacial attenuation. Attenuation exponentially depends on ice temperature, and can vary larger than the difference in the bed reflectivity for thawed and dry beds. In the 2016-17 austral summer, Alfred Wegener Institute carried out 150-MHz airborne radar survey for∼19,000 line kilometers in a 400-km by 400-km area including Dome Fuji, East Antarctica, where the Oldest Ice is predicted to present. Bed topography, roughness, and subglacial hydraulic potential were analyzed and subglacial lakes were preliminary mapped. We extend that study by rigorous analysis of bed returned power. We hypothesize that model-predicted thawed area is consistent with high bed reflectivity area derived from the radar data, when englacial attenuation/temperature is derived for the correct geothermal flux. We carried out attenuation and radar reflectivity estimates for a range of geothermalflux and mapped spatial variations in the attenuation and bed reflectivity.