solar.irradiance: Standard Solar Irradiance - Extraterrestrial and Terrestrial

Description Format Details Note Source References See Also



Three power spectra; from 280 to 1000 nm at 1 nm intervals. The unit is W*m^{-2}*nm^{-1}.


a transmittance spectrum = the quotient of 2 spectra from solar.irradiance


solar.irradiance is a colorSpec object with quantity equal to 'energy' and with 3 spectra:


Extraterrestrial Radiation (solar spectrum at top of atmosphere) at mean Earth-Sun distance


spectral radiation from solar disk plus sky diffuse and diffuse reflected from ground on south facing surface tilted 37 deg from horizontal


the sum of Direct and Circumsolar irradiance, when the optical path is 1.5 times that of the sun at zenith, see Details

atmosphere2003 is a colorSpec object with quantity equal to 'transmittance' and with 1 spectrum:


the quotient AirMass.1.5 / AirMass.0 from solar.irradiance


Direct is Direct Normal Irradiance Nearly parallel (0.5 deg divergent cone) radiation on surface with surface normal tracking (pointing to) the sun, excluding scattered sky and reflected ground radiation.

Circumsolar is Spectral irradiance within +/- 2.5 degree (5 degree diameter) field of view centered on the 0.5 deg diameter solar disk, but excluding the radiation from the disk.


The reference spectra in ASTM G173-03 are designed for Photovoltaic Performance Evaluation.

The original wavelength sequence in ASTM G173-03 is irregular. The interval is 0.5 nanometer from 280 to 400 nm, 1 nm from 400 to 1700 nm, an intermediate wavelength at 1702 nm, and 5 nm from 1705 to 4000 nm. To create the object solar.irradiance with a regular step size, the original was resampled from 280 to 1000 nm at 1nm intervals.


Reference Solar Spectral Irradiance: ASTM G-173.


ASTM G173-03 Reference Spectra Derived from SMARTS v. 2.9.2.
Standard Tables for Reference Solar Spectral Irradiances: Direct Normal and Hemispherical on 37-deg Tilted Surface (2003)

See Also

D65, D50, daylightSpectra, resample, vignette Blue Flame and Green Comet

colorSpec documentation built on Nov. 19, 2018, 5:06 p.m.