> "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."

I am trying to understand this. Normally the ocean waters around a region change temperature in unison -- the temperatures would gradually move up or down as with seasonal changes or some other slowly changing factor. However, an El Nino event would punctuate that scenario, creating a delta function in the hotspot NINO34 region.

I would venture that comparing a delta function against a surrounding area of gradual change would be a strong negative correlation. So this would intuitively decrease the link strength during an El Nino event.

Perhaps this is not surprising after all. Unless I am missing something obvious.