[1] Total solar radiation incident upon earth is estimated at 174 PW, [2] for a yearly total of 5,490,905 EJ. (reddit.com)
Accompanying changes in the Sun - Earth distance directly affect the amount of solar radiation incident in on the Earth in different parts of the year. (gcrio.org)
At each site, Fischer set up radiometers on four buildings — two with untreated roofs and two with treated roofs — to measure the amount of radiation incident on the roof as well as the radiation reflected off the roof. (newscenter.lbl.gov)