The sum of direct and scattered solar radiation reaching the ground after atmospheric weakening is called total solar radiation. On the global average, total solar radiation accounts for only 45% of the solar radiation reaching the upper limit of the atmosphere.
The following was contributed by Drs. Joanna Haigh and Willam Ball, February, 2016: The solar radiation arriving at Earth (once known as the “solar constant”, now usually referred to as Total Solar Irradiance (TSI), is the most fundamental of climate parameters as it indicates the totality of the energy driving the climate system.
The total solar radiation is maximum around noon in the day, and 0 at night. The radiation energy in VIS (0.4–0.76 μm), IR (>0.76) μm), and UV (<0.4 μm) accounts for 50%, 43%, and 7% of the total solar radiation respectively. Thus, the radiation energy is concentrated in the short-wave bands, and solar radiation is also called short-wave radiation.
On the global average, total solar radiation accounts for only 45% of the solar radiation reaching the upper limit of the atmosphere. The total radiation increases with the decrease in latitude and the increase in altitude. The total solar radiation is maximum around noon in the day, and 0 at night.
The average annual solar radiation arriving at the top of the Earth's atmosphere is about 1361 W/m 2. This represents the power per unit area of solar irradiance across the spherical surface surrounding the Sun with a radius equal to the distance to the Earth (1 AU).
This represents the power per unit area of solar irradiance across the spherical surface surrounding the Sun with a radius equal to the distance to the Earth (1 AU). This means that the approximately circular disc of the Earth, as viewed from the Sun, receives a roughly stable 1361 W/m 2 at all times.
OverviewTypesUnitsIrradiation at the top of the atmosphereIrradiance on Earth''s surfaceApplicationsSee alsoBibliography
There are several measured types of solar irradiance. • Total solar irradiance (TSI) is a measure of the solar power over all wavelengths per unit area incident on the Earth''s upper atmosphere. It is measured facing (pointing at / parallel to) the incoming sunlight (i.e. the flux through a surface perpendicular to the incoming sunlight; other angles would not be TSI and be r…