Transient radio wave scattering by aeration zones

It is shown that the availability of water can be detected only by reflection from a capillary fringe situated in a region contiguous with water. One has to take into account this result for a more exact determination of the water depth in ground. It has been established that the observed pulse acquires a duration above the source pulse. The calculation results have shown that measurement errors of frequency dependencies of permittivities and specific conductivities that are used as initial data manifest during the calculation of the diffraction fields for structures of large depth (that are more than 2-3 meters). This is a result of the small amplitudes of the pulses reflected from deep discontinuities. In fact these errors bring about a "false reflection" preceding reflections from the capillary fringe and water. This effect reveals a violation of the causality law and is a consequence of the disturbed connection between the real and imaginary parts of complex permittivity. As it is known, this connection is determined after the Kramers-Kronig relations. On this basis a conclusion is made about the necessity of refinement of the source experimental data.