I was only concerned with reproducing their calculation of link strength, and calculating simpler variants of link strength, not using that link strength to predict NINO34. The way that Ludescher et al go from link strength to El Nino predictions is pretty convoluted, and involves using the NINO34 as well as the link strength.

There does seem to be a meaningful relationship between link strength and nino34 in the sense that link strength tends to decrease *during* El Nino events.