pvlib.irradiance.get_ground_diffuse(surface_tilt, ghi, albedo=0.25, surface_type=None)[source]#

Estimate diffuse irradiance on a tilted surface from ground reflections.

Ground diffuse irradiance is calculated as

\[G_{ground} = GHI \times \rho \times \frac{1 - \cos\beta}{2}\]

where \(\rho\) is albedo and \(\beta\) is surface_tilt.

  • surface_tilt (numeric) – Surface tilt angles in decimal degrees. Tilt must be >=0 and <=180. The tilt angle is defined as degrees from horizontal (e.g. surface facing up = 0, surface facing horizon = 90).

  • ghi (numeric) – Global horizontal irradiance. \(W/m^2\)

  • albedo (numeric, default 0.25) – Ground reflectance, typically 0.1-0.4 for surfaces on Earth (land), may increase over snow, ice, etc. May also be known as the reflection coefficient. Must be >=0 and <=1. Will be overridden if surface_type is supplied.

  • surface_type (string, optional) – If supplied, overrides albedo. surface_type can be one of ‘urban’, ‘grass’, ‘fresh grass’, ‘snow’, ‘fresh snow’, ‘asphalt’, ‘concrete’, ‘aluminum’, ‘copper’, ‘fresh steel’, ‘dirty steel’, ‘sea’.


grounddiffuse (numeric) – Ground reflected irradiance. \(W/m^2\)


Table of albedo values by surface_type are from 2, 3, 4; see SURFACE_ALBEDOS.



Loutzenhiser P.G. et. al. “Empirical validation of models to compute solar irradiance on inclined surfaces for building energy simulation” 2007, Solar Energy vol. 81. pp. 254-267.


https://www.pvsyst.com/help/albedo.htm Accessed January, 2024.


http://en.wikipedia.org/wiki/Albedo Accessed January, 2024.


Payne, R. E. “Albedo of the Sea Surface”. J. Atmos. Sci., 29, pp. 959–970, 1972. DOI: 10.1175/1520-0469(1972)029<0959:AOTSS>2.0.CO;2