RF electrical properties of salty ice and frozen Earth

Abstract

RF losses at 100 Mc/s in artificial samples of salty ice and frozen, fresh‐water‐saturated earths were measured in the laboratory, and pronounced attenuation of radio waves within distances of a few meters are predicted as a general rule. Salty ice dielectric constants averaged 3.5, and resistivities ‘across the grain’ varied from about 55 ohm‐meters at −10°C to about 1200 ohm meters at −40°C for ice containing about 5% of salts. These results may or may not apply to natural sea ice and permafrost.

Field Measurements of Dielectric Absorption in Antarctic Ice and Snow at Very High Frequencies

“…The m easurem ents at V.H.F . by W estphal (p ersonal communication and in Ragle and others , 1964), Cook (1960) and the present author agree well with data extrapolated from m easurem ents on the relaxation spectrum of ice b y Auty and Cole ( 1952 ), Watt and Maxwell ( 1960) Watt and MaxweLL ( 1960 ). Field measurements on the relaxation spectrum of ice , Athabasca Glacier, Canada .…”

“…Except for the effects of infra-red absorption bands, the data in Figure 1 generally support this h ypothesis, and softan 8 is plotted as a fun ction of the impurity content of the ice with temperature as the only parameter in Fig ure 2. Cook ( 1960), W estphal, and Kuroiwa (1954) explicitly state the n a ture a nd concentration of major impurities in their samples but the present a uthor has estima ted the impurity concentrations for the remaining data in Figure 2 from the original papers. The impurity content of the Brunt I ce Shelf is no t directly known and the values in F igure 2 were assigned by comparison with the Maudheim ice shelf (Brocas and D elwiche, 1963 ;W a lford , unpublished ) .…”

“…The es timates of impurity concentrations are probably accura te only to a factor of three and no attempt has been made to take a ccount of differences in chemical composition between various samples. Such differences may be r a ther sma ll because four authors use samples of na turally occurring ice or snow , Cook (1960) m es ice of similar composition to natural sea ice a nd Auty a nd Cole ( 1952) use pure ice m a d e from conductivity wa ter.…”

Electrical Properties of Saline Ice

“…Cook (1960) measured artificial ice at 100 MHz only, obtaining Jnormalized) dielectric coefficients comparable with those of pure ice at this frequency. (Dorsey, 1940;Mantis, 1951).…”

“…DC measurements were also performed by Pounder and Little (1959). Literature searches by Cook (1960), Horigan (1953) and this laboratory have yielded few other direct references. Anderson (1960) has considered the electrical conductivity theoretically.…”