mlclouds.tfarms.tfarms

tfarms(tau, cloud_type, cloud_effective_radius, solar_zenith_angle, radius, Tuuclr, Ruuclr, Tddclr, Tduclr, albedo)[source]

Fast All-sky Radiation Model for Solar applications (FARMS).

Literature

[1] Yu Xie, Manajit Sengupta, Jimy Dudhia, “A Fast All-sky Radiation Model

for Solar applications (FARMS): Algorithm and performance evaluation”, Solar Energy, Volume 135, 2016, Pages 435-445, ISSN 0038-092X, https://doi.org/10.1016/j.solener.2016.06.003. (http://www.sciencedirect.com/science/article/pii/S0038092X16301827)

Variables

F0

Radiative flux at top of atmosphere

Fd

Direct solar flux in the downwelling direction at the surface (eq 2a from [1])

De

Effective cloud particle size (diameter).

Parameters:

  • tau (np.ndarray) – Cloud optical thickness (cld_opd_dcomp) (unitless).

  • cloud_type (np.ndarray) – Integer values representing different cloud types

  • cloud_effective_radius (np.ndarray) – Cloud effective particle radius (cld_reff_dcomp) (micron).

  • solar_zenith_angle (np.ndarray) – Solar zenith angle (degrees). Must represent the average value over the integration period (e.g. hourly) under scrutiny.

  • radius (np.ndarray) – Sun-earth radius vector, varies between 1.017 in July and 0.983 in January.

  • Tuuclr (np.ndarray) – Transmittance of the clear-sky atmosphere for diffuse incident and diffuse outgoing fluxes (uu). ***Calculated from multiple REST2 runs at different solar angles. Average of Tddclr w different solar angles (see eq 5 from [1]).

  • Ruuclr (np.ndarray) – Calculated in REST2. Aerosol reflectance for diffuse fluxes.

  • Tddclr (np.ndarray) – Calculated in REST2. Transmittance of the clear-sky atmosphere for direct incident and direct outgoing fluxes (dd). Tddclr = dni / etdirn

  • Tduclr (np.ndarray) – Calculated in REST2. Transmittance of the clear-sky atmosphere for direct incident and diffuse outgoing fluxes (du). Tduclr = dhi / (etdirn * cosz)

  • albedo (np.ndarray) – Ground albedo.

  • debug (bool) – Flag to output additional transmission/reflectance variables.

returns:

  • ghi (np.ndarray) – FARMS GHI values (this is the only output if debug is False).

  • fast_data (collections.namedtuple) – Additional debugging variables if debug is True. Named tuple with irradiance data. Attributes:

    ghi : global horizontal irradiance (w/m2) dni : direct normal irradiance (w/m2) dhi : diffuse horizontal irradiance (w/m2)