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What is ENSO? Page 2 - SSTs and trade winds

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  This is Page 2 of the sub-series "What is ENSO?". If you haven't already, please read Page 1 first. For convenience, keep that page open in a different tab. = = = What is ENSO? In the previous post , we learnt to identify ENSO phases from the perspective of sea surface temperature anomalies . In this post, I'm going to answer a question that no one really asked ―  What if I wanted to identify ENSO phases from the perspective of sea surface temperatures (SSTs) instead? What if, for no good reason but because I felt like it, I wanted to do away with the "anomalies" bit? Looking at SSTs instead of SST anomalies makes matters unnecessarily complicated, but we're going to do it anyway because it also teaches us a lot. In the image below, I've plotted SSTs from the HadISST dataset. These are mean SSTs for the months of December, January and February (DJF) over all years from 1872-2009. Why did we select the months of DJF? Because ENSO events can be seen