# pvlib.clearsky.haurwitz¶

pvlib.clearsky.haurwitz(apparent_zenith)[source]

Determine clear sky GHI using the Haurwitz model.

Implements the Haurwitz clear sky model for global horizontal irradiance (GHI) as presented in [1, 2]. A report on clear sky models found the Haurwitz model to have the best performance in terms of average monthly error among models which require only zenith angle [3].

Parameters

apparent_zenith (Series) – The apparent (refraction corrected) sun zenith angle in degrees.

Returns

ghi (DataFrame) – The modeled global horizonal irradiance in W/m^2 provided by the Haurwitz clear-sky model.

References

1

B. Haurwitz, “Insolation in Relation to Cloudiness and Cloud Density,” Journal of Meteorology, vol. 2, pp. 154-166, 1945.

2

B. Haurwitz, “Insolation in Relation to Cloud Type,” Journal of Meteorology, vol. 3, pp. 123-124, 1946.

3

M. Reno, C. Hansen, and J. Stein, “Global Horizontal Irradiance Clear Sky Models: Implementation and Analysis”, Sandia National Laboratories, SAND2012-2389, 2012.