bsrn.utils.calculations.calc_kb#

bsrn.utils.calculations.calc_kb(bni, zenith, bni_extra, min_mu0=0.065, max_beam_transmittance=1.0)[source]#

Calculates beam transmittance ($k_b$) following pvlib conventions [1] [2]. 按照 pvlib 惯例计算直射透射率 ($k_b$)。

$k_b = B_n / E_{0n}$, floored at $mu_0 ge$ min_mu0 for consistency, clamped to [0, max_beam_transmittance].

Parameters:

  • bni (numeric or Series) – Measured beam normal irradiance ($B_n$). [W/m^2] 测量的法向直接辐照度 ($B_n$)。[瓦/平方米]

  • zenith (numeric or Series) – True (not refraction-corrected) solar zenith angle ($Z$). [degrees] 真实（未经折射修正）太阳天顶角 ($Z$)。[度]

  • bni_extra (numeric or Series) – Extraterrestrial beam normal irradiance ($E_{0n}$). [W/m^2] 地外法向辐照度 ($E_{0n}$)。[瓦/平方米]

  • min_mu0 (float, default 0.065) – Minimum $mu_0$ to allow; timestamps where $mu_0 <$ min_mu0 yield $k_b = 0$. 允许的最小 $mu_0$；当 $mu_0 <$ min_mu0 时 $k_b = 0$。

  • max_beam_transmittance (float, default 1.0) – Upper clamp for $k_b$. $k_b$ 的上限。

Returns:

kb – Beam transmittance ($k_b$), clamped to [0, max_beam_transmittance]. [unitless] 直射透射率 ($k_b$)，限制在 [0, max_beam_transmittance]。[无单位]

Return type:

numeric or Series

References