Radio-frequency Attenuation Length, Basal Reflectivity, Depth, and Polarization Measurements from Moore’s Bay in the Ross Ice-Shelf

ABSTRACT. Radio-glaciological parameters from Moore’s Bay, in the Ross Ice Shelf, have been measured. The thickness of the ice shelf in Moore’s Bay was measured from reflection times of radio-frequency pulses propagating vertically through the shelf and reflecting from the ocean. The average depth obtained is 576 ± 8 m. The temperature-averaged attenuation length of the ice column, 〈L〉, is derived from the returned power assuming 100 % reflection. A linear fit to the data yields 〈L(ν) 〉 = (460 ± 20) − (180 ± 40)ν, for the frequencies ν =[0.100-0.850] GHz, at 95 % confidence. Introducing a baseline of 543±7 m between radio transmitter and receiver allowed the computation of the basal reflection coefficient, R, separately from attenuation. The electric-field reflection coefficient is R = 0.82 ± 0.07 across [0.100-0.850] GHz. Finally, the reflected power rotated into the orthogonal antenna polarization is less than 5 % below 0.400 GHz, compatible with air propagation. These results suggest that Moore’s Bay will serve as an appropriate medium for the ARIANNA high energy neutrino telescope