There are currently plenty of methods for Earth remote sensing that enable detecting areas with extensive radionuclide contamination. These methods rely on various physical principles. Each has specific limitations, benefits and shortcomings. A rapid development of radio electronics and digital technologies boosted evolution of the radio-wave imagery. In today's context, radiowave imagery is understood to mean a surveillance of objects in a radio band with a level of detail that only an optical system can allow at a significant distance with a broad ground swath, including the objects invisible in an optical range. This paper proposes a solution to one of the radio-wave imagery problems of detecting a weakly ionized low-temperature plasma that forms over the areas extensively contaminated by radionuclides against the Earth background from airborne and spaceborne systems. The methodical approach, as well as numerical results, are presented.