Can A Butterfly Change the Weather? |
 Dave Thurlow, Host |
Hi, I'm Dave Thurlow. Today on the Weather Notebook, producer Robin White finds out about the "butterfly theory" of why weather forecasts sometimes go wrong.
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| Edward Lorenz, the first to describe what is known as 'deterministic chaos' as a shaper of weather, and was the originator of the term 'the butterfly effect', plotted the three key variables in three dimensional space, he gained a plot that came to be known as the Lorenz Attractor. Exploratorium |
TP: People sometimes use the metaphor of "the butterfly effect" to describe this sensitivity of weather conditions to small errors. A butterfly flapping it's wings in a small area of Amazonia could affect the weather over London a week later.
RW: Whether or not it's literally true is a matter for debate, Palmer says, but the point is that the metaphor of the butterfly represents a small local air movement that can affect the weather thousands of miles away. Palmer follows a big storm backwards in time to show how it works. A few days before it arrived in London it was a smaller storm off the US coast.
TP: If you go back 10 days, it's just some little tiny disturbance somewhere over the Pacific or over east Asia...what caused that low pressure system over east Asia ten days ago? Well it might have been just some Chinese lady shaking her washing out on the clothes line.
RW: Another metaphor - but the point is that big weather has small beginnings. As a meteorologist, if you don't get those beginnings right - if you don't factor in the Chinese lady - you can end up making mistakes in the forecast. To increase accuracy, the European Center makes many forecasts a day, each time tweaking the data - adding a small inaccuracy, like the Chinese lady - to make more precise forecasts reflecting a range of variables.
Robin White is an independent producer from San Francisco. The Weather Notebook is underwritten by Subaru with major support provided by the National Science Foundation.