  The estimation of total solar irradiance falling on the earth's surface is
important in the field of solar energy generation and forecasting. Several
clear-sky solar radiation models have been developed over the last few decades.
Most of these models are based on empirical distribution of various
geographical parameters; while a few models consider various atmospheric
effects in the solar energy estimation. In this paper, we perform a comparative
analysis of several popular clear-sky models, in the tropical region of
Singapore. This is important in countries like Singapore, where we are
primarily focused on reliable and efficient solar energy generation. We analyze
and compare three popular clear-sky models that are widely used in the
literature. We validate our solar estimation results using actual solar
irradiance measurements obtained from collocated weather stations. We finally
conclude the most reliable clear sky model for Singapore, based on all clear
sky days in a year.
