Revealing the nature of radar reflections in ice: DEP-based FDTD forward modeling

摘要

Successful simulation of ground penetrating radar (GPR) traces in polar ice is achieved bynumerical finite-difference time-domain (FDTD) forward modeling.Properties of the modeled medium are taken from high resolution dielectric profiling (DEP)of the upper 100~m of an ice core from Dronning Maud Land, Antarctica.The GPR reference trace is calculated from stacking of a normal moveout correctedcommon-midpoint survey, carried out near the borehole location.The excellent agreement of synthetic and GPR-based results demonstrates the capability ofFDTD models to reproduce radargrams from ice core properties forinterpretation of radio echo sounding data, and emphasizes the exploitation of radar datafor improved interpretations of glaciological climate proxys.In addition to the presentation of modeling results, we perform sensitivity experiments toinvestigate the nature and origin of radar reflection in ice,discuss reasons for the failure of modeling studies in the past, and indicate new approaches.