Nonstandard Air Mass Zero
There are other AM0 (extraterrestrial, or ETR) solar spectra that have been derived since 1970. Several of these spectra are available as components in the MODTRAN and SMARTS models for atmospheric spectral transmission of sunlight.
The MODTRAN ETR spectra are high resolution, with approximately 50,000 data points at 1 wavenumber ( 1 cm-1) resolution.
The MODTRAN ETR spectra have been resampled for use with the SMARTS spectral code to 0.5 nm resolution between 280 nm and 400 nm, 1.0 nm resolution from 400 nm to 1700 nm, and 5 nm resolution between 1700 nm and 4000 nm, with a transition wavelength at 1702 nm. The resampling computed the equivalent average energy in the SMARTS2 band from the higher resolution MODTRAN data within the SMARTS2 band by integration over the bandwidth divided by the bandwidth.
For historical interest, we also provide the 1973 "Thekaekara" spectrum which is often quoted.
There are also extremely high resolution spectra (0.005 nm , or 5 angstroms or better) available at the following web and ftp download sites:
NOTE: this atlas contains over 1 million data points broken up into 1000 Angstrom wavelength band files.
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