Based on the academic paper "El Niño Normal" by J. Illingworth (commonly cited in oceanography and meteorology literature, specifically Weather, 1990, or similar climatology journals), here is the proper story of how our understanding of the Pacific Ocean changed.
This story moves from the chaos of early observations to the discovery of a rhythmic heartbeat that governs the world's weather. el nino normal illingworth pdf
Before we can understand the anomaly, we must understand the rule. The term "normal" in the keyword is deceptively simple. In climatology, "normal" refers to the average oceanic and atmospheric conditions over a 30-year period (typically updated every decade by the WMO). Based on the academic paper "El Niño Normal" by J
Academic PDFs hosted on personal university webpages often disappear when professors retire. If Illingworth taught at a university in the UK (e.g., University of Reading) or Australia (University of Melbourne), and his faculty page was removed in 2015, the PDF becomes a digital ghost. Part 1: Understanding the Baseline – What Does
Why is the word "Normal" so critical in this PDF? To appreciate this, we need to understand how El Niño is measured.
This is the most specific clue. In the context of environmental science and meteorology, John Illingworth (or a namesake) is less likely; however, "Illingworth" is a surname associated with technical documentation, statistical process control, and educational PDFs in the UK and Australia. Alternatively, within niche climate forums, "Illingworth" may refer to a forgotten technical author or a professor who published a short manual on ENSO neutral states in the late 1990s or early 2000s. The search volume suggests a specific, perhaps now-out-of-print, educational PDF.