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Name: Johnathan
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Location: South Africa
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What is the amount of infrared energy in sunlight that a) is radiated by the sun b) reaches Earth's surface? What percentage of the total light energy that reaches Earth's surface does it constitute?

The amount of electromagnetic radiation that is radiated by the Sun, and that reaches the surface of the Earth is not a constant. It depends upon solar activity, the angle of incidence which varies from place to place on the Earth as well as the season of the year, and a number of atmospheric conditions such as water vapor and cloud cover.

A Google search for the term "solar irradiance" provides a number of web sites that discuss the various parameters that affect the energy flux as a function of wavelength (frequency). One site is:

Vince Calder

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