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Abbot showed that one of Langley's corrections was erroneously applied. Abbot's results varied between 1.89 and 2.22 calories (1.318 to 1.548 kW/m 2), a variation that appeared to be due to the Sun and not the Earth's atmosphere. [7] In 1954 the solar constant was evaluated as 2.00 cal/min/cm 2 ± 2%. [8] Current results are about 2.5 percent ...
Solar radiation pressure on objects near the Earth may be calculated using the Sun's irradiance at 1 AU, known as the solar constant, or G SC, whose value is set at 1361 W/m 2 as of 2011. [17] All stars have a spectral energy distribution that depends on their surface temperature. The distribution is approximately that of black-body radiation.
The solar constant is a conventional measure of mean TSI at a distance of one astronomical unit (AU). Direct normal irradiance (DNI), or beam radiation, is measured at the surface of the Earth at a given location with a surface element perpendicular to the Sun direction. [6]
The solar constant is equal to approximately 1,368 W/m 2 (watts per square meter) at a distance of one astronomical unit (AU) from the Sun (that is, at or near Earth's orbit). [99] Sunlight on the surface of Earth is attenuated by Earth's atmosphere , so that less power arrives at the surface (closer to 1,000 W/m 2 ) in clear conditions when ...
Of the ~340 W/m 2 of solar radiation received by the Earth, an average of ~77 W/m 2 is reflected back to space by clouds and the atmosphere and ~23 W/m 2 is reflected by the surface albedo, leaving ~240 W/m 2 of solar energy input to the Earth's energy budget. This amount is called the absorbed solar radiation (ASR).
The intensity of solar irradiance including all wavelengths is the Total Solar Irradiance (TSI) and on average is the solar constant. It is equal to about 1361 W m −2 at the distance of Earth's annual-mean orbital radius of one astronomical unit and as measured at the top of the atmosphere. [ 42 ]
The first visible and electromagnetic effects of a solar flare reach observers on Earth at the speed of light, which means they were spotted about eight minutes after they occurred on the surface ...
The earth's atmosphere absorbs a considerable amount of the ultraviolet light. The resulting spectrum at the Earth's surface has fewer photons, but they are of lower energy on average, so the number of photons, above the bandgap, per unit of sunlight energy is greater than in space. This means that solar cells are more efficient at AM1 than AM0.