def cirrus_test(cirrus):
    """Cirrus TOA test, see (Zhu and Woodcock, 2015)

    The threshold is derived from (Wilson & Oreopoulos, 2013)

    Parameters
    ----------
    cirrus: ndarray

    Output
    ------
    ndarray: boolean
    """
    th_cirrus = 0.01
    return cirrus > th_cirrus
