Dear MA Ghorbani,
no I have not tried any other detrending methods, but the divergence is an effect that is reported in the scientific literature.
Looking at it, it does feel as if one should be able to change that by "suitable" detrending.
Marco
Marco, Thank you for sharing this excellent post.
Did you test alternative detrending methods, and if so, did they significantly affect the divergence observed after 1960?