Airborne Radio Echo Sounding (RES) measures on Alpine Glaciers to evaluate ice thickness and bedrock geometry: preliminary results from pilot tests performed in the Ortles Cevedale Group (Italian Alps).

The present study proposes a theoretical modeling of simultaneous and noninvasive measurements of electrical resistivity and dielectric permittivity using a quadrupole probe on a subjacent medium. A mathematical–physical model is applied to the propagation of errors in the measurement of resistivity and permittivity based on a sensitivity functions tool. The findings are also compared with results of the classical method of analysis in the frequency domain, which is useful for determining the behavior of zero and pole frequencies in the linear time invariant circuit of the quadrupole. This study underlines that average values of electrical resistivity and dielectric permittivity can be used to estimate complex impedance over various terrains and concretes, especially when they are characterized by low levels of water saturation (content), and are analyzed within a bandwidth ranging only from low to middle frequencies. To meet the design specifications, that ensure satisfactory performances of the probe (inaccuracies of no more than 10%), the forecasts provided by the sensitivity functions approach are discussed in comparison with those foreseen by the transfer functions method (in terms of both the band of frequency f and the measurable range of resistivity ρ, or permittivity εr).

In recent times, the GPR technique has assumed an important role in glacial environment exploration. Ice thickness, bedrock description, internal water floods or underground channel, glacial structures (as snow layering and crevasses detection) form part of our experience in Antarctica and in high alpine glacier ski areas. In this paper, we present some results of these investigations exploring the possibility of combining our technical expertise on Radio Echo Sounding (RES) instrumentation to develop a system for subglacial environment exploration.