18 Mar New edition of BètaBreak: the weather

Mathematician John Forbes Nash knew how to get the right girl.Mathematician John Forbes Nash knew how to get the right girl.

Nowadays we have access to a lot of information, including lots of different weather forecasts. But still it happens that you are standing in the rain, wearing your summer dress, because in the morning they predicted a sunny day. In the new BetaBreak, at 18 March in the central hall of the Faculty of Science, our most daily discussion will be treated, the weather.  How come that after centuries of science we are still not able to predict the weather exactly?

The weather caused by gods
The first thing to be blamed for the weather was a god or even several gods. In Greek mythology, more than fifteen gods were responsible for different types of weather, like sun, the north wind, the seasons. The most famous one is Helios,  God of the Sun, who drove with his chariot of the sun through the sky every day to bring light to the people.

Measuring the weather
In the early Renaissance, the Italian physicist Galileo Galilei was the first to start actually measuring the weather, he built the first thermometer.  He used the fact that the density of a liquid changes when the temperature changes. If you put different kinds of liquids in several glass vessels in a glass cylinder, you can observe what happens with the temperature. This is because of Archimedes Law; objects with a lower density will float and the ones with a higher density will sink.

Predicting the weather
After scientists started to measure the weather, they also tried to predict it. Scientists in the 19th century had a deterministic view, this means that they thought that every event must be caused by another event, so everything must be predictable. Norwegian meteorologist and mathematician Vilhelm Bjerknes made complicated models that should predict the weather infinitely, if you would know the exact conditions and places of the weather at a certain time.
Unfortunately, Bjerknes did not succeed.  Some decades later, the British thinker Lewis Fry Richardson tried to simplify his models. He did this by cutting up the atmosphere in pieces. This technique is still used by the KNMI by Sander Tijm, one of the guests of the upcoming BetaBreak. Richardson dreamed of a big hall where infinitely many ‘computers’ (humans that are calculating) are working to predict the weather.
Although Richardson’s dream is written down rather poetical (Outside are playing fields, houses, mountains and lakes, for it was thought that those who compute the weather should breathe of it freely), it makes you think of the supercomputers that are now used to predict the weather.

Computing the weather in 24 hours
After Richardson, one of the founders of the modern computer, John von Neumann, made the first automatic weather prediction for the next 24 hours. One minor problem was that the computers took about 24 hours. But this development was very hopeful, because the only thing that was needed were more ‘people’ in the big hall of Richardson. Since the developments of computers were going very fast, a perfect and longterm prediction of the weather didn’t seem far away.

But mathematician and meteorologist Edward made an end to Richardson’s dream. He discovered that weather is chaotic. This means that a small change somewhere might cause an exponential difference. This is what he would call the butterfly effect;The flap of the wings of one butterfly in Brasil could cause a Tornado in Texas, so to speak. The fact that weather is chaotic ensures that there is a limit to every predicting model. This limit lies around ten days. This is the reason why we will never be able to predict if there will be an Elfstedentocht (the famous Dutch iceskating ride) next year.

Current state of science and future
So far the history of weather forecasting. But what is the state of science nowadays? How do current scientist deal with the limits that are caused by chaos? And how can a weatherman communicate this insecurity to the public? This is what is going to be asked at the coming BetaBreak with our guests:

  • Sander Tijm, meteorologist.
  • Huub Mizee, weatherman.
  • Robert Mureau, meteorologist.

Be there, at 18 March, 12 o’clock, in the Central Hall of Science Park 904! And tell us afterwards what you thought of it!

WTF mariebeth

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