Solar irradiance spectrum at top of atmosphere.

Solar radiation is radiant energy emitted by the sun from a nuclear fusion reaction that creates electromagnetic energy. The spectrum of solar radiation is close to that of a black body with a temperature of about 5800 K. About half of the radiation is in the visible short-wave part of the electromagnetic spectrum. The other half is mostly in the near-infrared part, with some in the ultraviolet part of the spectrum. ^[1] The ultraviolet radiation not absorbed by the atmosphere or other protective coating is responsible for the change of color in skin pigments. Spectrum of solar irradiance at top of Earths atmosphere. ... Spectrum of solar irradiance at top of Earths atmosphere. ... Radiant energy is the energy of electromagnetic waves. ... The Sun (Latin: Sol) is the star at the center of the Solar System. ... The deuterium-tritium (D-T) fusion reaction is considered the most promising for producing fusion power. ... In most modern usages of the word spectrum, there is a unifying theme of between extremes at either end. ... As the temperature decreases, the peak of the black body radiation curve moves to lower intensities and longer wavelengths. ... This article or section does not cite any references or sources. ... Legend γ = Gamma rays HX = Hard X-rays SX = Soft X-Rays EUV = Extreme ultraviolet NUV = Near ultraviolet Visible light NIR = Near infrared MIR = Moderate infrared FIR = Far infrared Radio waves EHF = Extremely high frequency (Microwaves) SHF = Super high frequency (Microwaves) UHF = Ultra high frequency VHF = Very high frequency HF = High... Image of two girls in mid-infrared (thermal) light (false-color) Infrared (IR) radiation is electromagnetic radiation of a wavelength longer than that of visible light, but shorter than that of radio waves. ... “UV” redirects here. ... Natural Ultramarine pigment in powdered form. ...

Solar radiation is commonly measured with a pyranometer or pyrheliometer. A pyranometer is a type of actinometer used to measure broadband solar irradiance on a planar surface. ...

Solar constant

A 1903 Langley bolograph with an erroneous solar constant of 2.54 calories.

The solar constant is the amount of incoming solar electromagnetic radiation per unit area, measured on the outer surface of Earth's atmosphere, in a plane 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 watts per square meter,^[2] (it fluctuates by about 6.9% during a year - from 1412 W/m² in early January to 1321 W/m² in early July and by a few parts per thousand from day to day). Thus, for the whole Earth, with a cross section of 127,400,000 km², the power is 1.740×10¹⁷ W plus-minus 3.5%. The solar constant is not quite constant over long time periods either; see solar variation. Image File history File links Size of this preview: 800 × 179 pixel Image in higher resolution (1550 × 346 pixel, file size: 134 KB, MIME type: image/png) 1911 article Sun, figure 12. ... Image File history File links Size of this preview: 800 × 179 pixel Image in higher resolution (1550 × 346 pixel, file size: 134 KB, MIME type: image/png) 1911 article Sun, figure 12. ... Electromagnetic waves can be imagined as a self-propagating transverse oscillating wave of electric and magnetic fields. ... Adjectives: Terrestrial, Terran, Telluric, Tellurian, Earthly Atmosphere Surface pressure: 101. ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... The watt (symbol: W) is the SI derived unit of power, equal to one joule per second. ... A square metre (US spelling: square meter) is by definition the area enclosed by a square with sides each 1 metre long. ... A 3-D view of a beverage-can stove with a cross section in yellow. ... This page lists examples of the power in watts produced by various different sources of energy. ... The watt (symbol: W) is the SI derived unit of power, equal to one joule per second. ... 400 year history of sunspot numbers. ...

The solar constant is relatively constant, but varies according to sunspot activity. It affects mainly long-term climates, rather than short-term weather. The Earth receives a total amount of radiation determined by its cross section (π R²), but as the planet rotates this energy is distributed across the entire surface area (4 π R²). Hence, the average incoming solar radiation (known as "insolation") is one fourth the solar constant or ~342 W/m². At any given location and time, the amount received at the surface depends on the state of the atmosphere and the latitude. A sunspot is a region on the Suns surface (photosphere) that is marked by a lower temperature than its surroundings and intense magnetic activity, which inhibits convection, forming areas of low surface temperature. ... A 3-D view of a beverage-can stove with a cross section in yellow. ... Area is the measure of how much exposed area any two dimensional object has. ... TOA and surface insolation, annual mean Insolation is the incoming solar radiation that reaches a planet and its atmosphere or, by extension, any object exposed to solar rays, such as watts per square meter of Sun-facing cross section, across the entire electromagnetic spectrum; most of that power is in... Latitude, usually denoted symbolically by the Greek letter phi, , gives the location of a place on Earth north or south of the equator. ...

The solar constant includes all wavelengths of solar electromagnetic radiation, not just the visible light. (See electromagnetic spectrum for more details) It is linked to the apparent magnitude 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. The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... Legend γ = Gamma rays HX = Hard X-rays SX = Soft X-Rays EUV = Extreme ultraviolet NUV = Near ultraviolet Visible light NIR = Near infrared MIR = Moderate infrared FIR = Far infrared Radio waves EHF = Extremely high frequency (Microwaves) SHF = Super high frequency (Microwaves) UHF = Ultra high frequency VHF = Very high frequency HF = High... The apparent magnitude (m) of a star, planet or other celestial body is a measure of its apparent brightness as seen by an observer on Earth. ...

In 1884 Samuel Pierpont Langley attempted to estimate the solar constant from Mount Whitney in California, and (by taking readings at different times of day) attempted to remove atmospheric absorption effects. However he obtained the incorrect value of 2903 W/m², perhaps due to mathematical errors. Between 1902 and 1957, measurements by Charles Greeley Abbot 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, and his results varied between 1.89 and 2.22 calories, and the variation appeared to be solar, not terrestrial.^[3] Samuel Pierpont Langley. ... Mount Whitney is the highest point in the contiguous United States at elevation 14,505 feet (4,421 meters). ... Charles G. Abbot, at the 9th Annual Aircraft Engineering Research Conference, 1934 Charles Greeley Abbot (May 31, 1872 Wilton, NH – December 17, 1973, Washington D.C.) was an American astrophysicist, astronomer and Secretary of the Smithsonian Institution. ...

The angular diameter of Earth seen from the sun is ca. 1/11,000 radian, so the solid angle of Earth seen from the sun is ca. 1/140,000,000 steradian. Thus, the sun emits about 2 billion times the amount of radiation that is caught by Earth, or about 3.86×10²⁶ watts.^{[citation needed]} The angular diameter of an object as seen from a given position is the diameter measured as an angle. ... Some common angles, measured in radians. ... A solid angle is the three dimensional analog of the ordinary angle. ... The steradian (ste from Greek stereos, solid) is the SI derived unit of solid angle, and the 3-dimensional equivalent of the radian. ...

Climate effect of solar radiation

Further information: Solar dimming and Insolation

Solar irradiance spectrum above atmosphere and at surface

On Earth, solar radiation is obvious as daylight when the sun is above the horizon. 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 sunshine, a combination of bright yellow light (sunlight in the strict sense) and heat. The heat on the body, on objects, etc., that is directly produced by the radiation should be distinguished from the increase in air temperature. Global dimming is the gradual reduction in the amount of global direct irradiance at the Earths surface that was observed for several decades after the start of systematic measurements in 1950s. ... TOA and surface insolation, annual mean Insolation is the incoming solar radiation that reaches a planet and its atmosphere or, by extension, any object exposed to solar rays, such as watts per square meter of Sun-facing cross section, across the entire electromagnetic spectrum; most of that power is in... Image File history File links No higher resolution available. ... Image File history File links No higher resolution available. ... Horizon. ... Prism splitting light High Resolution Solar Spectrum Sunlight in the broad sense is the total spectrum of the electromagnetic radiation given off by the Sun. ... Fig. ...

The amount of radiation intercepted by a planetary body varies as the square of the distance between the star and the planet. The Earth's orbit and obliquity change with time (over thousands of years), sometimes forming a nearly perfect circle, and at other times stretching out to an orbital eccentricity of 5% (currently 1.67%). The total insolation remains almost constant but the seasonal and latitudinal distribution and intensity of solar radiation received at the Earth's surface also varies ^[4]. 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 ages (see: Milankovitch cycles). Two bodies with a slight difference in mass orbiting around a common barycenter. ... Axial tilt is an astronomical term regarding the inclination angle of a planets rotational axis in relation to its orbital plane. ... (This page refers to eccitricity in astrodynamics. ... TOA and surface insolation, annual mean Insolation is the incoming solar radiation that reaches a planet and its atmosphere or, by extension, any object exposed to solar rays, such as watts per square meter of Sun-facing cross section, across the entire electromagnetic spectrum; most of that power is in... Variations in CO2, temperature and dust from the Vostok ice core over the last 400 000 years For the animated movie, see Ice Age (movie). ... Milankovitch cycles are the collective effect of changes in the Earths movements upon its climate, named after Serbian civil engineer and mathematician Milutin Milanković. The eccentricity, axial tilt, and precession of the Earths orbit vary in several patterns, resulting in 100,000 year ice age cycles of the...

Notes

1. ^ http://www.grida.no/climate/ipcc_tar/wg1/041.htm#121
2. ^ Construction of a Composite Total Solar Irradiance (TSI) Time Series from 1978 to present. Retrieved on October 5, 2005.
3. ^ This article incorporates text from the Encyclopædia Britannica Eleventh Edition article "Sun", a publication now in the public domain.
4. ^ Graph of variation of seasonal and latitudinal distribution of solar radiation

October 5 is the 278th day of the year (279th in leap years) in the Gregorian calendar. ... 2005 (MMV) was a common year starting on Saturday of the Gregorian calendar. ... Encyclopædia Britannica, the 11th edition The Encyclopædia Britannica Eleventh Edition (1910–1911) is perhaps the most famous edition of the Encyclopædia Britannica. ... The public domain comprises the body of all creative works and other knowledge—writing, artwork, music, science, inventions, and others—in which no person or organization has any proprietary interest. ...

See also

• Insolation : a measure of solar radiation energy incident on a surface.
• Solar heating : Predicting solar heating effects.
• Solar neutrino problem: solar neutrino measurement problem
• Solar variation: variations in solar activity
• Solar wind: particles flowing from the Sun
  • Coronal mass ejection: large ejection of electrons and protons
  • Polar aurora: usually electrons hitting Earth's atmosphere
  • Solar flare: eruption creates increase of solar wind particles
  • Solar proton event: protons hitting Earth's atmosphere
  • Pyranometer: solar radiation sensor

TOA and surface insolation, annual mean Insolation is the incoming solar radiation that reaches a planet and its atmosphere or, by extension, any object exposed to solar rays, such as watts per square meter of Sun-facing cross section, across the entire electromagnetic spectrum; most of that power is in... Solar heating is a style of building construction which uses the energy of sunshine to heat a structure. ... The solar neutrino problem was a major discrepancy between measurements of the neutrinos flowing through the Earth and theoretical models of the solar interior, lasting from the mid-1960s to about 2002. ... 400 year history of sunspot numbers. ... The plasma in the solar wind meeting the heliopause For the British comic, see Solar Wind (comic). ... A composite image showing two CMEs (at 2 oclock and 8 oclock), with the sun at center. ... Aurora borealis Polar aurorae are optical phenomena characterized by colorful displays of light in the night sky. ... A Solar Flare and CME, courtesy NASA A solar flare is a violent explosion in the Suns atmosphere with an energy equivalent to a billion megatons, traveling normally at about 1 million km per hour (about 0. ... The plasma in the solar wind meeting the heliopause For the British comic, see Solar Wind (comic). ... A Solar Proton Event occurs when high-energy protons, ejected from the suns surface during a solar flare, get caught by the Earths magnetic field and cause ionization in the ionosphere. ... A pyranometer is a type of actinometer used to measure broadband solar irradiance on a planar surface. ...

External links

• Solar radiation - Encyclopedia of Earth
• Total solar irradiance data archive 1978-2007 at the website of the National Geophysical Data Center
• A Comparison of Methods for Providing Solar Radiation Data to Crop Models and Decision Support Systems, Rivington et al.
• Evaluation of three model estimations of solar radiation at 24 UK stations, Rivington et al.
• High resolution spectrum of solar radiation from Observatoire de Paris
• Solar Position Calculator Compute the position of the sun, or rise and set times and positions.
• Measuring Solar Radiation : A lesson plan from the National Science Digital Library.
• Websurf astronomical information : 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.
• Daylength - Formulas to calculate the daylength depending from latitude and day of year.
• An Excel workbook with a solar position and solar radiation time-series calculator; by Greg Pelletier
• DOE information about the ASTM standard solar spectrum for PV evaluation.
• ASTM Standard for solar spectrum at ground level in the US (latitude ~ 37 degrees).

v • d • e The Sun
Structure	Solar core - Radiation zone - Convection zone
Atmosphere	Photosphere - Chromosphere - Transition region - Corona
Extended structure	Termination Shock - Heliosphere - Heliopause - Heliosheath - Bow Shock
Solar phenomena	Sunspots - Faculae - Granules - Supergranulation - Solar Wind - Spicules - Coronal loops - Solar Flares - Solar Prominences - Coronal Mass Ejections - Moreton Waves - Coronal Holes
Other	Solar System - Solar Variation - Solar Dynamo - Heliospheric Current Sheet - Solar Radiation - Solar Eclipse - Spectral Class: G2

The National Geophysical Data Center (NGDC) provides scientific stewardship, products and services for geophysical data describing the solid earth, marine, and solar-terrestrial environment, as well as earth observations from space. ... The Paris Observatory (in French, Observatoire de Paris or Observatoire de Paris-Meudon) is the foremost astronomical observatory of France, and one of the largest astronomical centers in the world. ... The Sun (Latin: Sol) is the star at the center of the Solar System. ... The structure of the Sun The core of the Sun is considered to extend from the center to about 0. ... The radiation zone is the middle zone in the suns interior. ... The convection zone is the outermost layer of the suns interior. ... Image File history File links Sun920607. ... Photo taken during the French 1999 eclipse The stellar atmosphere is the outer region of the volume of a star, lying above the stellar core, radiation zone and convection zone. ... The photosphere of an astronomical object is the region at which the optical depth becomes one for a photon of wavelength equal to 5000 angstroms. ... The chromosphere (literally, color sphere) is a thin layer of the Suns atmosphere just above the photosphere, roughly 10,000 kilometers deep (approximating to, if a little less than, the diameter of the Earth). ... TRACE 19. ... A corona is a type of plasma atmosphere of the Sun or other celestial body, extending millions of kilometres into space, most easily seen during a total solar eclipse, but also observable in a coronagraph. ... The locations of Voyagers 1 and 2 as of 2005 In space physics, the termination shock is the boundary marking one of the outer limits of the suns influence. ... The heliosphere is a bubble in space produced by the solar wind. ... The heliopause is the boundary between the heliosphere and the interstellar medium outside the solar system. ... The locations of Voyagers 1 and 2 as of 2005 The heliosheath is the zone between the termination shock and the heliopause at the outer border of the solar system. ... In a planetary magnetosphere, the bow shock is the boundary at which the solar wind abruptly drops as a result of its approach to the magnetopause. ... A sunspot is a region on the Suns surface (photosphere) that is marked by a lower temperature than its surroundings and intense magnetic activity, which inhibits convection, forming areas of low surface temperature. ... A facula (plural: faculae) is literally a bright spot. ... Solar photosphere Granules on the photosphere of the Sun are caused by convection currents of plasma within the Suns convective zone. ... Supergranulation is one of the influences on the Sun. ... The plasma in the solar wind meeting the heliopause For the British comic, see Solar Wind (comic). ... A spicule is a dynamic jet of about 500km diameter on the Sun. ... Typical coronal loops observed by TRACE Coronal loops form the basic structure of the lower corona and transition region of the Sun. ... A Solar Flare and CME, courtesy NASA A solar flare is a violent explosion in the Suns atmosphere with an energy equivalent to a billion megatons, traveling normally at about 1 million km per hour (about 0. ... Filaments surrounding a solar flare, caused by the interaction of the plasma in the Suns atmosphere with its magnetic field. ... A composite image showing two CMEs (at 2 oclock and 8 oclock), with the sun at center. ... Animation of a Moreton wave which occurred on December 6, 2006 A Moreton wave is a kind of shockwave on the Suns chromosphere. ... Coronal holes are areas where the Suns corona is darker, colder, and has lower-density plasma than average. ... Major features of the Solar System (not to scale; from left to right): Pluto, Neptune, Uranus, Saturn, Jupiter, the asteroid belt, the Sun, Mercury, Venus, Earth and its Moon, and Mars. ... 400 year history of sunspot numbers. ... The solar dynamo is the physical process that generates the Suns magnetic field. ... Heliospheric current sheet The Heliospheric current sheet (HCS) is the surface within the Solar System where the polarity of the Suns magnetic field changes from north to south. ... Solar irradiance spectrum at top of atmosphere. ... Photo taken during the 1999 eclipse. ... In astronomy, stellar classification is a classification of stars based initially on photospheric temperature and its associated spectral characteristics, and subsequently refined in terms of other characteristics. ...