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NREL - National Renewable Energy Laboratory
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The Simple Model of the Atmospheric Radiative Transfer of Sunshine, or SMARTS, predicts clear-sky spectral irradiances. Earth's atmosphere is a continuously changing filter that modifies the sunlight that travels through it. SMARTS computes how changes in the atmosphere affect the distribution of solar power or photon energy for each wavelength of light.

SMARTS is a versatile model that is used by researchers in a number of fields. For example, solar energy researchers use SMARTS to test the performance of spectroradiometers, develop reference spectra, establish uniform testing conditions for materials research, optimize daylighting techniques, and verify broadband radiation models. Researchers also use SMARTS in the fields of architecture, atmospheric science, photobiology, and health physics.

SMARTS is a complex model that requires significant experience and knowledge of basic physics and meteorology, climatology, or atmospheric sciences. It is therefore used primarily by researchers and engineers.

Learn more about the SMARTS model or register to download it.

SMARTS 2.9.5 User alert

February 25, 2010

A bug has been identified in SMARTS 2.9.5 PC package, the file name for the Sand and Gravel Albedo file is presently "SndGravl.dat" but SHOULD BE "SndGrvl.dat". Users can fix the problem by renaming the file in the "Albedo" folder. The download file has been updated.

SMARTS was developed by Dr. Christian Gueymard.


SMARTS supports the U.S. Department of Energy's Solar Energy Technologies Program.

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