pvlib.spectrum.spectral_factor_caballero(precipitable_water, airmass_absolute, aod500, module_type=None, coefficients=None)[source]#

Estimate a technology-specific spectral mismatch modifier from airmass, aerosol optical depth, and atmospheric precipitable water, using the Caballero model.

The model structure was motivated by examining the effect of these three atmospheric parameters on simulated irradiance spectra and spectral modifiers. However, the coefficient values reported in 1 and available here via the module_type parameter were determined by fitting the model equations to spectral factors calculated from global tilted spectral irradiance measurements taken in the city of Jaén, Spain. See 1 for details.

  • precipitable_water (numeric) – atmospheric precipitable water. [cm]

  • airmass_absolute (numeric) – absolute (pressure-adjusted) airmass. [unitless]

  • aod500 (numeric) – atmospheric aerosol optical depth at 500 nm. [unitless]

  • module_type (str, optional) –

    One of the following PV technology strings from 1:

    • 'cdte' - anonymous CdTe module.

    • 'monosi', - anonymous sc-si module.

    • 'multisi', - anonymous mc-si- module.

    • 'cigs' - anonymous copper indium gallium selenide module.

    • 'asi' - anonymous amorphous silicon module.

    • 'perovskite' - anonymous pervoskite module.

  • coefficients (array-like, optional) – user-defined coefficients, if not using one of the default coefficient sets via the module_type parameter.


modifier (numeric) – spectral mismatch factor (unitless) which is multiplied with broadband irradiance reaching a module’s cells to estimate effective irradiance, i.e., the irradiance that is converted to electrical current.



Caballero, J.A., Fernández, E., Theristis, M., Almonacid, F., and Nofuentes, G. “Spectral Corrections Based on Air Mass, Aerosol Optical Depth and Precipitable Water for PV Performance Modeling.” IEEE Journal of Photovoltaics 2018, 8(2), 552-558. DOI: 10.1109/jphotov.2017.2787019