solar.irradiance:
Standard Solar Irradiance - Extraterrestrial and Terrestrial
Description
solar.irradiance
Three power spectra; from 280 to 1000 nm at 1 nm intervals. Units are $W*m^{-2}*nm^{-1}$.
atmosphere2003
a transmittance spectrum = a ratio of 2 spectra from solar.irradiance
Format
solar.irradiance is a
colorSpec object with quantity equal to 'power' and with 3 spectra:
AirMass.0- Extraterrestrial Radiation (solar spectrum at top of atmosphere) at mean Earth-Sun distance
GlobalTilt- spectral radiation from solar disk plus sky diffuse and diffuse reflected
from ground on south facing surface tilted 37 deg from horizontal
AirMass.1.5- the sum of Direct and Circumsolar irradiance, see Details
atmosphere2003 is a colorSpec object with quantity equal to 'transmittance' and with 1 spectrum:
AirMass.1.5- the ratio of
AirMass.1.5/AirMass.0 from solar.irradiance
Source
http://rredc.nrel.gov/solar/spectra/am1.5/astmg173/astmg173.htmlDetails
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.
References
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)