pvlib.albedo.inland_water_dvoracek

pvlib.albedo.inland_water_dvoracek(solar_elevation, surface_condition=None, color_coeff=None, wave_roughness_coeff=None)

Estimation of albedo for inland water bodies.

The available surface conditions are for inland water bodies, e.g., lakes and ponds. For ocean/open sea, see pvlib.albedo.SURFACE_ALBEDOS.

Parameters:

• solar_elevation (numeric) – Sun elevation angle. [degrees]

• surface_condition (string, optional) –

  If supplied, overrides color_coeff and wave_roughness_coeff. surface_condition can be one of the following:

  • 'clear_water_no_waves'

  • 'clear_water_ripples_up_to_2.5cm'

  • 'clear_water_ripples_larger_than_2.5cm_occasional_whitecaps'

  • 'clear_water_frequent_whitecaps'

  • 'green_water_ripples_up_to_2.5cm'

  • 'muddy_water_no_waves'

• color_coeff (float, optional) – Water color coefficient. [-]

• wave_roughness_coeff (float, optional) – Water wave roughness coefficient. [-]

Returns:

albedo (numeric) – Albedo for inland water bodies. [-]

Raises:

• ValueError – If neither of surface_condition nor a combination of color_coeff and wave_roughness_coeff are given. If surface_condition and any of color_coeff or wave_roughness_coeff are given. These parameters are mutually exclusive.

• KeyError – If surface_condition is invalid.

Notes

The equation for calculating the albedo \(\rho\) is given by

(1)\[ \rho = c^{(r \cdot \sin(\alpha) + 1)}\]

Inputs to the model are the water color coefficient \(c\) [-], the water wave roughness coefficient \(r\) [-] and the solar elevation \(\alpha\) [degrees]. Parameters are provided in [1] , and are coded for convenience in WATER_COLOR_COEFFS and WATER_ROUGHNESS_COEFFS. The values of these coefficients are experimentally determined.

Surface and condition	Color coefficient (\(c\))	Wave roughness coefficient (\(r\))
Clear water, no waves	0.13	0.29
Clear water, ripples up to 2.5 cm	0.16	0.70
Clear water, ripples larger than 2.5 cm (occasional whitecaps)	0.23	1.25
Clear water, frequent whitecaps	0.30	2.00
Green water, ripples up to 2.5cm	0.22	0.70
Muddy water, no waves	0.19	0.29

References

[1]

Dvoracek M.J., Hannabas B. (1990). “Prediction of albedo for use in evapotranspiration and irrigation scheduling.” IN: Visions of the Future American Society of Agricultural Engineers 04-90: 692-699.

Examples using pvlib.albedo.inland_water_dvoracek

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