def METHOD_NAME(R):
    """Function to remove the rain/no-rain discontinuity.
    It can be used before computing Fourier filters to reduce
    the artificial increase of power at high frequencies
    caused by the discontinuity.
    Parameters
    ----------
    R: array-like
        Array of any shape to be transformed.
    Returns
    -------
    R: array-like
        Array of any shape containing the transformed data.
    """
    R = R.copy()
    zerovalue = np.nanmin(R)
    threshold = np.nanmin(R[R > zerovalue])
    R[R > zerovalue] -= threshold - zerovalue
    R -= np.nanmin(R)
    return R