Earth Resistivity and Permittivity

Earth resistivity, as mentioned earlier, is quite weather/climate dependent. The resistivity after rain is lower than that measured during dry days. Also, it may be frequency dependent. The frequency dependence of the earth permittivity might be far more significant than that of the earth resistivity. Furthermore, water (H2O), which is a dominant factor of the earth permittivity, is extremely temperature dependent [18]. As a result, an error due to uncertainty of the earth resistivity and permittivity might be far greater than that due to the incompleteness of the earth-return impedance derived by Carson and Pollaczek. This fact should be reminded as a physical reality and engineering practice. 

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