@staticmethod
def net_shortwave_radiation(rs, albedo):
    """The net shortwave radiation (:math:`R_{ns}`) *[MJ/m²day]* resulting from the balance between incoming
        and reflected solar radiation as defined in
        `FAO 56 <http://www.fao.org/tempref/SD/Reserved/Agromet/PET/FAO_Irrigation_Drainage_Paper_56.pdf>`_
        (eq. 38, p. 51):

        .. math::

            R_{ns} = (1 − \\alpha) R_s

        :param rs: daily shortwave radiation (:math:`R_s`) *[MJ/m²day]*. See :meth:`shortwave_radiation`
        :type rs: float or np.array
        :param albedo: albedo or reflection coefficient (:math:`\\alpha` *[-]*). Range:
            :math:`0.0  \\leq \\alpha \\leq 1.0` (:math:`\\alpha=0.23` for the hypothetical grass reference crop).
            See :class:`PenmanMonteithDaily` and :meth:`et0`
        :type albedo: float or np.array
        :return: (*float or np.array*) daily net shortwave radiation (:math:`R_{ns}`) *[MJ/m²day]* reaching the earth
        """
    return (1.0 - albedo) * rs
