Effects of the Interaction of Microwave Radiation with the Atmosphere on the Passive Remote Sensing of the Earth’s Surface: Problems and Solutions (Review)

The main problems in the remote passive location of positions on the Earth’s surface are reviewed in detail. The first is related to the source of incoherent microwave radiation represented by a layer of two-temperature nonequilibrium ionospheric plasma at an altitude of ca. 80–110 km, which is located below a low Earth-orbiting satellite and formed under the influence of solar activity. As a result, the satellite receives direct radiation from this layer as well as reflected radiation from the Earth’s surface. The next problem is the attenuation of the intensity of the incident radiation as a result of the scattering of radio waves by charged aerosol layers located below the luminous layer. Aerosol particles are affected by solar and cosmic radiation and electronic and ionic attacks, due to which they become charged. Aerosol particles directly take part in the formation of a complete balance of charges in the atmosphere and are an effective catalyst for many physicochemical processes in neutral gaseous media. The processes related to the formation of aerosol particles, the kinetics of formation of their charge, and the processes of their interaction with incoherent microwave radiation are considered. This gives rise to the need to develop a fundamentally new scheme of passive location. Three possible versions of the arrangement of measurements are analyzed. In the first version, a complete set of measurements is implemented when the receiving equipment is simultaneously installed on the Earth, an aircraft, and a low Earth-orbiting satellite; in the second version, the receiving equipment is simultaneously installed on an aircraft and a satellite; in the third version, only on one satellite. The separation of the contributions of direct and reflected incoherent radiation received by the satellite can be achieved only using a special mathematical approach to the information processing (wavelet analysis), which has been under actively development in recent years. We fully show its broad possibilities for solving geophysical problems and discuss the problems of the calibration of the measuring equipment, which are associated with taking into account the superposition of two types of radiation coming to a satellite and with variation of the main parameters (concentration, flux density, and temperature of electrons) of the nonequilibrium two-temperature plasma in time.