Bird Simple Spectral Model:


The authors are Dr. Richard Bird and Dr. Carol Riordan. The FORTRAN compilation was done by Dr. Christian Guyemard after finding that simply downloading the code available in the Appendix of the HTML version of SERI technical report SERI/TR-215-2436 and compiling it would not result in a working model. Dr. Guyemard created the necessary input files, and compiled the FORTRAN code using Lahey FORTRAN V 4.5 to create an executable for the PC platform.

The FORTRAN verison of the model computes clear sky spectral direct beam, hemispherical diffuse, and hemispherical total irradiances on a prescribed receiver plane - tilted or horizontal - at a single point in time. For tilted planes, the user specifiy the incidence angle of the direct beam. The wavelength spacing is irregular, covering 122 wavelengths from 305 nm to 4000 nm. Aerosol optical depth, total precipitable water vapor (cm), and equivalent ozone depth (cm) must be specified by the user. No variations in atmospheric constituents or structure are available. There is no separate computation of circumsolar radiation. The direct beam spectral irradiance is assumed to contain the circumsolar radiation within a 5° solid angle. No smoothing functions are provided.


The ZIP file includes the following:

  • SPCTRAL2_PC.f - the FORTRAN code
  • SPCTRAL2_PC.exe - the compiled FOTRAN executable
  • SPCTRAL2_TAPE1.txt - a text file containing required input parameters
  • SPCTRAL2_TAPE2.txt - a text file containing extraterrestrial spectral irradiance and absorption coefficients
  • SPCTRAL2_OUTPUT.txt - text file containing example output

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