Clear sky irradiance simulation in a mountainous region in Brazil

Clear sky irradiance simulation in mountainous regions generally has problematic questions due to the heterogeneous topography. It is presented here a way to model irradiance by calculating radiative transfer through the atmosphere and surface parameters like sky view factors and terrain configuration over a digital elevation model. This is made using the Unix-based freeware Image Processing Workbench (IPW). Standard atmosphere parameters from a global aerosol data set (GADS) were used for a radiative transfer approach. An albedo map retrieved from Landsat images was also used in this simulation. Finally irradiance values retrieved by automatic meteorological stations could be utilized to generate correction factors indicating the atmosphere attenuation over irradiance for different highs.