Wind Gusts

Podcast

Wind Gusts

Transcript

Why the wind isn't steady. I'm Bob Hirshon and this is Science Update.

Today's question blew in from Will Cossel, of Auburn, California.

Cossel:
Why is it that the wind gusts? Instead of coming in one steady stream.

We asked Matt Peroutka, a research meteorologist at the National Weather Service in Silver Spring, Maryland.

Peroutka:
If our earth were perfectly flat, and the sun didn't rise or set, we would find that the wind would blow in a steady stream across the planet.

But obviously, that's not the case. The Earth's surface is peppered with hills, mountains, and tall buildings. These big objects can block the air. And the valleys and channels between them create bottlenecks, which force the wind through faster.

Dr. Peroutka says the sun also stirs things up. That's because it often warms up neighboring areas unevenly -- for instance, because of scattered clouds. When that happens, the hot air in the sunny spots rises, and the cool, shaded air rushes in from nearby. That creates gusty drafts.

Peroutka:
And typically once the sun begins to set or is past its greatest heating of the day, typically 3 or 4 in the afternoon, we'll see the gustiness decrease remarkably.

If you've got a science question, the answer isn't blowin' in the wind. It's here at 1-800-WHY-ISIT. If we use your question on the show you'll get a free Science Update mug.

For the American Association for the Advancement of Science, I'm Bob Hirshon.

Making Sense of the Research

We may not pay much attention to it, but all around us are phenomena that result from the physics and chemistry of our planet as it rotates and revolves around the sun. These include such things as night and day, the tides, the seasons, rain, and many others. We understand these phenomena by understanding the science that underlies them.

As you just learned, in this Science Update a caller asked why wind is so gusty. Why doesn't it just blow at the same speed all the time? Or not at all?

As you considered your own answers to these questions, hopefully you considered all of the factors that might affect the motion of air. Just one example is the fact that air acts like a fluid: temperature changes its density and obstacles change its rate of flow, just as with water in a lake or river.

Now try to answer the following questions:

1. What features of the Earth can cause the wind to blow in gusts?
2. How does the sun affect the wind?
3. During what period of time during the day does wind gustiness usually decrease?
4. What might change the world's wind patterns?
5. How would that affect us?
6. What would happen if there were fewer mountains?Or lots more skyscrapers? Or if the earth rotated more quickly or slowly? Or if more clouds blocked the sunlight?
7. What are some other factors that could affect how the wind blows?

Going Further

For a good follow-up to this Science Update, go to the Science NetLinks lesson called Properties of Air. This lesson helps demonstrate that air takes up space and puts pressure, or pushes, on everything around it.

You might also want to try NOVA Online’s El Niño, which looks at how this particular phenomenon affects weather patterns.