Dustin Schroeder¹, Winnie  Chu¹

¹Stanford University, Stanford, United States

Geothermal heat flux exerts a fundamental control on the behavior, stability, and evolution of ice sheets. However, this basal boundary is also exceedingly difficult and costly to measure directly. Geophysical remote sensing technique provides a cheap and effective way to constrain the distribution of geothermal heat that is critical for the initialization and spin-ups of predictive ice sheet models. Airborne ice penetrating radar sounding can provide observations of englacial and subglacial conditions at the catchment- to continent-scale. Specifically, the character and strength of radar bed echoes encode information about the thermal and hydrologic state of the ice sheet and its bed. While on an echo-by-echo basis, this information is highly non-unique, on a regional basis advanced radar processing approaches can disambiguate englacial- and subglacial-genic signals. However, even high-fidelity basal condition mapping does not directly map geothermal heat flux .  This requires careful and creative application of hydrological, geologic, and glaciological assumptions and information to the parameter estimation problem.  However, despite these considerable challenges, we will demonstrate how to combine radar sounding data with subglacial hydrologic and thermo-mechanical models to place meaningful observational constraints geothermal heat flux in a range of glaciological settings. We present a range of promising applications and problems for these approaches as well as their underlying assumptions, enabling conditions, and inherent limitations.