def METHOD_NAME(array):
    """Extrapolate NaN-values (missing) towards seafloor"""
    filled = False
    for i in range(1, array.shape[0]):
        mask = np.isnan(array[i,:,:])
        if np.sum(mask) > 0:
            array[i, mask] = array[i-1, mask]
            filled = True
    return filled