Premium
Dielectric properties of thawed active layers overlying permafrost using radar at VHF
Author(s) -
Arcone Steven A.,
Delaney Allan J.
Publication year - 1982
Publication title -
radio science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.371
H-Index - 84
eISSN - 1944-799X
pISSN - 0048-6604
DOI - 10.1029/rs017i003p00618
Subject(s) - reflectometry , permafrost , dielectric , radar , ground penetrating radar , materials science , active layer , volume (thermodynamics) , geology , time domain , environmental science , soil science , composite material , layer (electronics) , optoelectronics , physics , telecommunications , oceanography , computer science , quantum mechanics , computer vision , thin film transistor
Field measurements of the dielectric constant of thawed active layers of up to 1 m in depth at four sites in Alaska have been made using short‐pulse ground radar whose returns were received in the near‐field radiation zone. Three sites consisted of saturated silts with varying amounts of organic material, and the fourth site was a moist sand. The reflector returning the radar signals was the active layer/permafrost interface. Analysis of the waveforms showed that all the materials were nondispersive over the radar pulse bandwidth (75–225 MHz), and this was confirmed by time domain reflectometry (TDR) studies of field samples. The average dielectric constants were between 23 and 34 for the silts, which averaged between 45 and 50% water by volume, while the sandy site gave an average value of about 12 for a probable water content of about 23% by volume. These values are very similar to the laboratory work of others and were also confirmed by TDR. The high dielectric constants of the saturated materials allowed accurate profiling of active layer depth, and an example is presented. More detail would probably be achieved with a higher‐frequency radar.