Modelling of radiative transfer of natural surfaces in the solar radiation spectrum: development of a satellite data simulator (SDDS)

Abstract

The paper presents a newly developed radiative transfer model (SDDS) that simulates the reflected and emitted radiations of natural scenes with atmosphere from the visible to infrared spectrum. The software, SDDS, written in Visual Basic^®, simulates the radiation transfer processes in the ‘Earth–atmosphere’ system, and calculates the interaction between electromagnetic rays and the elements of the terrestrial medium. Its approach combines analytical and spatial discretization approaches, working with natural and urban landscapes. The Earth scene is discretized as a matrix of cells, the type of each cell being defined by the material it contains, and thus a cell can be ‘soil’, ‘vegetation’, ‘water’, etc. Rays are tracked in the Earth scene until their energy is smaller than a previously defined threshold. The intercepted rays are stored in the cells and are scattered later to the other layers of the scene. SDDS can be used to provide simulated satellite data under different conditions (view directions, spatial resolutions, atmosphere, etc.) and for different types of sensors, while addressing problems of identification and classification in satellite imagery. A range of possible applications of this model is highlighted, and further work needed for 3D modelling is also discussed. The first validation tests against other models are very encouraging.