def ra_clear_horizontal(Bhc, Dhc):
    """    
    Computes the clear sky beam irradiance on a horizontal surface

    .. math ::
        G_{hc}=B_{hc}+D_{hc}

    Parameters
    ----------
    Bhc : float
        beam irradiance at a horizontal surface
        :math:`B_{hc}`
        [W/m2]
    Dhc : float
        Diffuse irradiance at a horizontal surface
        :math:`D_{hc}`
        [W/m2]
        
    Returns
    -------
    ra_hor_clear_i : float
        Total clear-sky irradiance on a horizontal surface
        :math:`G_{hc}`
        [W/m2]

    Examples
    --------
    """
    ra_clear_hor = Bhc + Dhc
    return ra_clear_hor
