Weather Whys; Fractals

This is weather wise. As scientists learn more about the patterns and structures of weather phenomena in the atmosphere, they often find that some of those phenomena have similar features that turn up on a smaller and smaller scale. And when something shows that characteristic, scientists call it fractal behavior. As an example, say you're standing several yards away from a sign on which you see the letter Q. But as you walk closer, you see that the larger letter Q was made by writing and arranging a great number of smaller cues. The large Q could be said to have a fractal structure since its small scale elements look the same as the large element. Scientists say the atmosphere has a fractal structure. For instance, take the familiar low pressure system with fronts like you see on TV weather maps. It may produce thunderstorms for communities in its path. But scientists have found that within those thunderstorms is often a miniature version

of a low pressure system, and there may even be a surge of rain-cooled air which rushes down through the cloud and out ahead of it. That surge is a small scale cold front. Clouds and lightning are other examples of meteorological phenomena that appear to have fractal behavior. The study of fractals in meteorology is interesting, but it's not yet clear if it will lead to any new understanding of weather activity or to improved weather forecasts. Weather wise is produced with the assistance of the National Weather Service Forecast Office and the National Severe Storms Laboratory, both in Norman, Oklahoma, and the Cooperative Institute for Mesoscale Meteorological Studies, the Oklahoma Climate Illogical Survey, and the School of Meteorology, all at the University of Oklahoma. Our writer is Christine Harbour, our editor is Brian Walkie, and our executive producer is Karen Holt. Weather wise is made possible by a grant from the National Science Foundation. I'm Drew Barlow.