Processing of the multi-wave remote sensing data for ecological risk monitoring of the Chernobyl area

V. Lyalko, L. Wolfson, V. Shevchenko, I. Shevchenko
National Academy of Science of the Ukraiine

Studies of ecological after-effects of the Chernobyl nuclear accident have involved modern remote sensing techniques (air and space) in wave ranges from gamma- to radio-bands. The efficiency of the method mainly depends on a complex data interpretation which was under research.

The study area encompassed more than 10 000 kmē including not only the 30 km radius around Chernobyl but also adjacent territories at risk down to the northern suburb of Kiev, and the 50 km coastline of the Kiev water reservoir. Data were used from the satellites SPOT, Landsat, Cosmos in the optical range, the shuttle imaging radar data in the microwave range and aerial data, obtained from the CARTE laboratory aircraft, in gamma-, visible, IR- and microwave ranges. These data have allowed to map the radionuclide land contamination (mainly 137Cs), soil temperature, soil moisture, depth of the ground water level, as well as to investigate the reflected spectrum of the vegetation. Image interpretation revealed the main structures of damage propagation; particular attention has been given to the centres of the intersections of the multi-oriented faults which have importance in the territory structure and stipulate high soil permeability.

Processing of the aerial IR- and microwave data has permitted to locate areas with a high soil moisture and areas of high ground water levels close to the surface. Mainly from the survey work the presence of hydrogeological "windows" could be detected and mapped where ground water filtration takes place. Such areas are associated with tectonic faults, under which, as a result of the neotectonic processes, the permeability of the thin confining layer rises and a hydraulic connection between the infiltrating and ground water forms.

Superimposition of the radionucleidic and heavy metal contamination maps with the locations of hydrogeological "windows" permitted to predict the most probable pollution ways of the ground water. Data overlay and mass transport modelling was performed with the help of a GIS.