pvlib.irradiance.clearness_index_zenith_independent#

pvlib.irradiance.clearness_index_zenith_independent(clearness_index, airmass, max_clearness_index=2.0)[source]#

Calculate the zenith angle independent clearness index.

See [1] for details.

Parameters:

clearness_index (numeric) – Ratio of global to extraterrestrial irradiance on a horizontal plane. [unitless]
airmass (numeric) – Airmass. See airmass_relative. [unitless]
max_clearness_index (numeric, default 2.0) – Maximum value of the clearness index. The default, 2.0, allows for over-irradiance events typically seen in sub-hourly data. NREL’s SRRL Fortran code used 0.82 for hourly data.

Returns:

kt_prime (numeric) – Zenith-independent clearness index. [unitless]

References