A vigorous R&D program on solar concentrating power plants has been recently funded in Italy in order to demonstrate the feasibility of these technologies. Maps of direct normal radiation (DNI) are needed for the selection of construction sites for demonstration plants. This paper describes SOLARMET, a physical model that simulates the atmospheric effect on solar radiation. The SOLARMET model may be used to determine the solar radiation, total and direct, reaching the ground, based on information provided by satellite images. Atmosphere transmissivity, ground reflection coefficient, and other essential parameters in the model were determined from SBDART, a radiative transfer model, developed at University of California. Validation of the model have been carried out at Casaccia (Rome-Italy) ENEA centre. The results obtained in the 2002 year are encouraging. The difference between measured and calculated data, during this year, either for direct or global radiation, are lower than 6% on monthly basis. (c) 2006 Elsevier Ltd. All rights reserved.