Studies on solar radiation have become important for renewable energy issues stemming from oil crises and other environmental problems, thus increasing the need of reliable measurements of surface solar radiation. Six locations in Tamil Nadu were chosen for the study and global solar radiation was measured continuously for a period of one year along with relevant meteorological parameters. It was observed that the levels of solar radiation varied from a minimum of 1.9 kWh/m²/day during post monsoon season to a maximum of 6.6 kWh/m²/day during pre-monsoon season. Metronome and Bird clear sky models were validated for the selected locations. Results of the statistical indicators – Root Mean Square Error (RMSE) and Index of Agreement (D) showed that the models had excellent performance accuracy.

Keywords: Solar Radiation; Meteonorm Model; Bird Clear Sky Model; Statistical Analysis;