I did a training interval example in [comment #43](http://forum.azimuthproject.org/discussion/comment/14498/#Comment_14498).
You have to remember that the validation results for typical El Nino projections are only good for a few months to a year or two out. Or at least that is the impression I get. Yet here is a case in that the back-prediction is coherent in phase to 100 years prior to the start of the training interval !
I am beginning to think that this is all toy physics, with the caveat that toy physics usually doesn't work so well in real life. In this case it works out because no one ever thought to solve the wave equation with the known forcings. IMO, this is no longer a statistical question but a question in the philosophy of climate science modeling. Are these kinds of simple first-order models not acceptable by the standards of the climate science establishment? Just asking because I don't have a clue.
Last year a buddy of mine who works in the CompSci department at the local U got us hooked up with a climate scientist that is working with his former thesis advisor. This is one of those data mining research projects whereby they plow through satellite data looking for correlations and patterns. Over lunch at a local restaurant, I explained to him what my ENSO model was all about and he seemed interested in it. This scientist has written several papers on QBO and ENSO and so we thought it might go somewhere in the next several months. After keeping him informed of the progress and what I was also doing on the Azimuth Forum, we have completely lost contact since then. No replies to any emails.