Even though several groups of scientists hold different opinions on the prediction of the ENSO’s frequency in the future, they all agree that the predictions depend on many other complicated processes such as cloud feedback, etc. Therefore, so far no one can give a comprehensive answer to the future ENSO’s frequency. In this post, I will explain two extreme theories of the prediction.
Before I introduce El Niño and its impact, let’s first have a glimpse of Walker Circulation. (Figure 1).
Figure 1. Walker Circulation (http://www.youtube.com/watch?v=f-r82_HRfNw)
When an El Niño (the boy in Spanish) event happens, the normal location of Indonesian Low continuously moves eastward, which eventually reverses the high-low pressure relation. The eastward moving Indonesian Low weakens the strength of the southeastern trade wind and the upwelling at southeastern Pacific.