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Solar radiation

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	Solar radiation
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	Topics Solar radiation Topic Home Solar radiation is radiant energyFacts About Radiant energy Radiant energy is the energy of electromagnetic waves.... emitted by a sunStar Overview A star is a massive, compact body of plasma in outer space that is held together by its own gravity and, unlike a planet, is... as a result of its nuclear fusionNuclear fusion In physics, nuclear fusion is the process by which multiple nuclei join together to form a heavier nucleus.... reactions. The spectrumSpectrum Summary A spectrum is a condition or value that is not limited to a specific set of values but can vary infinely within a continuum... of the SunSun \|+ The Sun \|+\|-\| colspan="2" align="center" \| \|-... 's solar radiation is close to that of a black bodyBlack body In physics, a black body is an object that absorbs all electromagnetic radiation that falls onto it.... with a temperature of about 5,800 KKelvin Overview The Kelvin scale is a temperature scale where absolute zero—the coldest possible temperature where there is no heat en... . About half that lies in the visibleLight Light is electromagnetic radiation with a wavelength that is visible to the eye or, in a technical or scientific context, e... short-wave part of the electromagnetic spectrumElectromagnetic spectrum Overview The electromagnetic spectrum is the range of all possible electromagnetic radiation.... and the other half mostly in the near-infraredInfrared Infrared radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of... part. Some also lies in the ultravioletUltraviolet Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than soft X... part of the spectrum. When ultraviolet radiation is not absorbed by the atmosphere or other protective coating, it can cause a change in human skin pigmentationFacts About Pigment A pigment is a material that changes the color of light it reflects as the result of selective color absorption.... . Solar radiation is commonly measured with a pyranometerPyranometer Summary A pyranometer is a type of actinometer used to measure broadband solar irradiance on a planar surface.... or pyrheliometer. Solar constant The Solar constant is the amount of the Sun's incoming electromagnetic radiationElectromagnetic radiation Electromagnetic radiation is generally described as a self-propagating wave in space with electric and magnetic components.... (Solar radiation) per unit area, measured on the outer surface of Earth's atmosphereEarth's atmosphere Earth's atmosphere is a layer of gases surrounding the planet Earth and retained by the Earth's gravity.... in an aircraft perpendicular to the rays. The Solar constant includes all types of Solar radiation, not just the visible light. It is measured by satellite to be roughly 1366 wattWatt Summary The watt is the SI derived unit of power, equal to one joule per second.... s per square meterSquare metre The square meter is the SI derived unit of area, with symbol m².... (W/m²), though this fluctuates by about 6.9% during a year (from 1412 W/m² in early January to 1321 W/m² in early July) due to the earth's varying distance from the Sun, and by a few parts per thousand from day to day. Thus, for the whole EarthEarth Earth is the third planet in the solar system in terms of distance from the Sun, and the fifth largest.... (which has a cross sectionCross section (geometry) In geometry, a cross section is the intersection of a body in 2-dimensional space with a line, or of a body in 3-dimensional... of 127,400,000 km²Square kilometre Square kilometre, symbol km, is an SI unit of surface area.... ), the power is 1.740×10¹⁷Orders of magnitude (power) This page lists examples of the power in watts produced by various different sources of energy.... WWatt The watt is the SI derived unit of power, equal to one joule per second.... , plus or minus 3.5%. The Solar constant does not remain constant over long periods of time (see Solar variationSolar variation Solar variations are fluctuations in the amount of energy emitted by the Sun.... ). 1366 W/m² is equivalent to 1.96 calories per minute per square centimeter, or 1.96 langleys (Ly) per minute. The Earth receives a total amount of radiation determined by its cross section (p·r²), but as it rotates this energy is distributed across the entire surface areaSurface area Surface area is the measure of how much exposed area an object has.... (4·p·r²). Hence the average incoming Solar radiation (sometimes called the Solar irradianceIrradiance Irradiance, radiant emittance, and radiant exitance are radiometry terms for the power of electromagnetic radiat... ), taking into account the angle at which the rays strike and that at any one moment half the planet does not receive any solar radiation, is one-fourth the Solar constant (approximately 342 W/m²). At any given moment, the amount of Solar radiation received at a location on the Earth's surface depends on the state of the atmosphere and the location's latitudeFacts About Latitude Latitude, usually denoted symbolically by the Greek letter f , gives the location of a place on Earth north or south of the ... . The Solar constant includes all wavelengths of Solar electromagnetic radiation, not just the visible light (see Electromagnetic spectrumElectromagnetic spectrum The electromagnetic spectrum is the range of all possible electromagnetic radiation.... ). It is linked to the apparent magnitudeApparent magnitude The apparent magnitude of a star, planet or other celestial body is a measure of its apparent brightness as seen by an obse... of the Sun, −26.8, in that the Solar constant and the magnitude of the Sun are two methods of describing the apparent brightness of the Sun, though the magnitude only measures the visual output of the Sun. In 1884, Samuel Pierpont LangleySamuel Pierpont Langley Samuel Pierpont Langley was an American astronomer, physicist, inventor of the bolometer and pioneer of aviation.... attempted to estimate the Solar constant from Mount WhitneyMount Whitney Mount Whitney is the highest point in the contiguous United States at elevation 14,505 feet.... in California. By taking readings at different times of day, he attempted to remove effects due to atmospheric absorption. However, the value he obtained, 2903 W/m², was still too great. Between 1902 and 1957, measurements by Charles Greeley AbbotCharles Greeley Abbot Charles Greeley Abbot was an American astrophysicist, astronomer and Secretary of the Smithsonian Institution.... and others at various high-altitude sites found values between 1322 and 1465 W/m². Abbott proved that one of Langley's corrections was erroneously applied. His results varied between 1.89 and 2.22 calories (1318 to 1548 W/m²), a variation that appeared to be due to the Sun and not the Earth's atmosphere. The angular diameterAngular diameter The angular diameter of an object as seen from a given position is the diameter measured as an angle.... of the Earth as seen from the Sun is approximately 1/11,000 radianRadian The radian is a unit of plane angle.... s, meaning the solid angleFacts About Solid angle The solid angle, O, that an object subtends at a point is a measure of how big that object appears to an observer at tha... of the Earth as seen from the sun is approximately 1/140,000,000 steradianSteradian The steradian is the SI unit of solid angle.... s. Thus the Sun emits about two billion times the amount of radiation that is caught by Earth, in other words about 3.86×10²⁶ watts. Climate effect of solar radiation On Earth, solar radiation is obvious as daylight when the sun is above the horizonHorizon The horizon is the line that separates earth from sky.... . This is during daytime, and also in summer near the poles at night, but not at all in winter near the poles. When the direct radiation is not blocked by clouds, it is experienced as sunshineSunlight Sunlight in the broad sense is the total spectrum of electromagnetic radiation given off by the Sun.... , combining the perception of bright white light (sunlight in the strict sense) and warming. The warming on the body and surfaces of other objects is distinguished from the increase in air temperature. The amount of radiation intercepted by a planetary body varies inversely with the square of the distance between the star and the planet. The Earth's orbitORBit ORBit is a CORBA compliant Object Request Broker.... and obliquity change with time (over thousands of years), sometimes forming a nearly perfect circle, and at other times stretching out to an orbital eccentricityOrbital eccentricity In astrodynamics, under standard assumptions any orbit must be of conic section shape.... of 5% (currently 1.67%). The total insolationInsolation Insolation is the incoming solar radiation that reaches a planet and its atmosphere or, by extension, any object exposed to ... remains almost constant but the seasonal and latitudinal distribution and intensity of solar radiation received at the Earth's surface also varies. For example, at latitudes of 65 degrees the change in solar energy in summer & winter can vary by more than 25% as a result of the Earth's orbital variation. Because changes in winter and summer tend to offset, the change in the annual average insolation at any given location is near zero, but the redistribution of energy between summer and winter does strongly affect the intensity of seasonal cycles. Such changes associated with the redistribution of solar energy are considered a likely cause for the coming and going of recent ice ageIce age An ice age is a period of long-term downturn in the temperature of Earth's climate, resulting in an expansion of the contine... s (see: Milankovitch cyclesMilankovitch cycles Milankovitch cycles are the collective effect of changes in the Earth's movements upon its climate, named after Serbian civi... ). See also InsolationInsolation Insolation is the incoming solar radiation that reaches a planet and its atmosphere or, by extension, any object exposed to ... : a measure of solar radiation energy incident on a surface Solar heatingSolar heating Solar heating is a style of building construction which uses the energy of sunshine to provide heat in a structure.... : Predicting solar heating effects Solar neutrino problemSolar neutrino problem The solar neutrino problem was a major discrepancy between measurements of the numbers of neutrinos flowing through the Eart... : solar neutrino measurement problem Solar variationSolar variation Solar variations are fluctuations in the amount of energy emitted by the Sun.... : variations in solar activity Solar windSolar wind Soup alla Canavese is a soup made from white stock, butter, onions, carrot, celery, tomato puree, cauliflower, fat bacon, pa... : particles flowing from the Sun Coronal mass ejectionCoronal mass ejection A coronal mass ejection is an ejection of material from the solar corona, observed with a white-light coronagraph.... : large ejection of electrons and protons Polar aurora: usually electrons hitting Earth's atmosphere Solar flareSolar flare A solar flare is a violent explosion in the Sun's atmosphere with an energy equivalent to tens of millions of hydrogen bombs... : eruption creates increase of solar windSolar wind Soup alla Canavese is a soup made from white stock, butter, onions, carrot, celery, tomato puree, cauliflower, fat bacon, pa... particles Solar proton eventSolar proton event A Solar proton event occurs when high-energy protons, ejected from the sun's surface during a solar flare, get caught by the... : protons hitting Earth's atmosphere PyranometerPyranometer A pyranometer is a type of actinometer used to measure broadband solar irradiance on a planar surface.... : solar radiation sensor External links at the website of the National Geophysical Data CenterNational Geophysical Data Center Overview The National Geophysical Data Center provides scientific stewardship, products and services for geophysical data describing ... , Rivington et al. , Rivington et al. from Observatoire de Paris : A lesson plan from the National Science Digital Library. : Online tools for calculating Rising and setting times of Sun, Moon or planet, Azimuth of Sun, Moon or planet at rising and setting, Altitude and azimuth of Sun, Moon or planet for a given date or range of dates, and more. - Formulas to calculate the daylength depending from latitude and day of year. with a solar position and solar radiation time-series calculator; by about the ASTM standard solar spectrum for PV evaluation. for solar spectrum at ground level in the US (latitude ~ 37 degrees).