def body_ref_from_glob_horiz(glob_horiz_solar, floor_reflectance=0.25,
    sky_exposure=1, fract_efficiency=0.725):
    """Estimate floor-reflected solar flux on human geometry from global horizontal solar.

    Args:
        glob_horiz_solar: Global horizontal solar irradiance in W/m2.
        floor_reflectance: A number between 0 and 1 the represents the
            reflectance of the floor. Default is for 0.25 which is characteristic
            of outdoor grass or dry bare soil.
        sky_exposure: A number between 0 and 1 representing the fraction of the
            sky vault in occupant’s view. Default is 1 for outdoors in an
            open field.
        fract_efficiency: A number representing the fraction of the body
            surface exposed to radiation from the environment. This is typically
            either 0.725 for a standing or supine person or 0.696 for a seated
            person. Default is 0.725 for a standing person.
    """
    return (0.5 * sky_exposure * fract_efficiency * glob_horiz_solar *
        floor_reflectance)
