Direct insolation is the solar insolation measured at a given location on Earth with a surface element perpendicular to the Sun's rays, excluding diffuse insolation (the solar radiation that is scattered or reflected by atmospheric components in the sky). Direct insolation is equal to the solar constant minus the atmospheric losses due to absorption and scattering. While the solar constant varies with the Earth-Sun distance and solar cycles, the losses depend on the time of day (length of light's path through the atmosphere depending on the Solar elevation angle), cloud cover, moisture content, and other impurities.
Read more about Direct Insolation: Average Direct Insolation, Units of Measurement
Famous quotes containing the word direct:
“You see how this House of Commons has begun to verify all the ill prophecies that were made of it—low, vulgar, meddling with everything, assuming universal competency, and flattering every base passion—and sneering at everything noble refined and truly national. The direct tyranny will come on by and by, after it shall have gratified the multitude with the spoil and ruin of the old institutions of the land.”
—Samuel Taylor Coleridge (1772–1834)