IRS-1C LISS III land cover maps at different spatial resolutions used in real-time accidental air pollution deposition modelling

Remote-sensing scenes can provide information highly useful for real-time modelling of the atmospheric deposition in the case of an accidental nuclear release. Accurate prediction of spatial patterns in the deposition is vital to establish countermeasures to avoid unnecessary exposure of the public. This is demonstrated by a hypothesised case for a nuclear power plant in Lithuania. From classification analysis a number of land cover classes are mapped in an IRS-1C LISS III scene. The roughness of each land cover class is assigned and used as input to a real-time dispersion model. Calculation results with input of a high-resolution roughness map provide the most realistic deposition pattern. A scale analysis of degrading the land cover map into lower resolutions is performed. The atmospheric deposition model results based on lower resolution roughness maps are compared and evaluated by the so-called Dose Isopleth Correlation Area (DICA) method. The recommendation is that a 1-km resolution is adequate for real-time deposition modelling. Furthermore, the land cover mapping should be performed with care. Temporal variations in roughness at a seasonal time scale should be considered.