The forecasts are produced by a computer model that we call the "Hybrid Coupled Model", or HCM for short. It's "hybrid" in the sense that it's a big, complicated ocean model coupled to a much simpler, statistical atmospheric model. Other El Niño prediction models, by contrast, take differing approaches to the problem; some have simpler ocean models, and some have more complex atmospheres. The HCM falls somewhere in between. If you are interested in the gory technical details, I've made available a Technical Note (pdf) that describes the model, but, as I said, it's pretty gory and pretty technical.
What might be more interesting to see is how well the model performs. The correlation in the Pacific shows that the model does quite well at a 6-month lead time over the tropical Pacific strip, and quite respectably at a 12-month lead time. Part of our work here is to make the model perform even better.
Last modified: 25 June 1997
Copyright © 2000 David W. Pierce. All rights reserved.