Comprehensive review on empirical models to estimate global solar radiation on horizontal surfaces

In the present scenario of global warming and climate change, use of solar energy is becoming imminent. Researchers are working on developing models to predict global solar radiation based on meteorological and geographical parameters. A number of models have been developed in the past which have been summarized in the present study. The techniques to develop models have also been presented. In the era of global warming, the role of air pollutants in estimating GSR is more important than developing very complex models. Models related to this aspect have also been discussed.