There are well documented ways of seeing how much sunlight hits the Earth’s surface. What is far more rare however is the ability to accurately model this light. In this study they came up with a “flexible and efficient” algorithm that can be used to quickly calculate the solar radiation that makes contact with Earth. They calculated the radiation by using the direct and diffuse irradiation from all directions. The next step they took was to calculate all radiance, including that coming from reflections and accounting for the angles of the light. Next they evaluated any obstructions in the sky. They did this by using aerial photographs of the area during the times of interest. This study is important because it has major applications in agriculture, forestry, hydrology, and ecology. Solar radiation is the most potent form of energy we have on Earth, with these types of studies and models we can learn how to better utilize this energy source. Using these models we can improve agriculture and eventually even improve our ability to use solar power.
Rich, P. M., Dubayah, R., Hetrick, W. A., & Saving, S. C. (1994). Using viewshed models to calculate intercepted solar radiation: applications in ecology. American Society for Photogrammetry and Remote Sensing Technical Papers. In American Society of Photogrammetry and Remote Sensing (pp. 524-529).