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Weather
People normally talk about the weather because they cannot think of anything else to say - but sometimes it can be genuinely interesting. Did you know that weather gods are the oldest gods? Zeus and Yahwe started off as electrical storms and desert winds, precisely because such phenomena are so difficult to control and to understand. Not a great deal has changed - the weather still has the power to enthral and inspire, and destroy.
Predicting the weather is as old as the hills. The earliest methods verged on the superstitious or were simply anecdotal - a feeling in one's bones or the observed migration of birds. However, even modern weather forecasting methods are a far-from-exact science. Measuring the temperature, pressure, humidity, and movement of a layer of air fifteen kilometres high is hard enough, let alone predicting what it will do tomorrow. In Touch talks to Mike Edwards of General and Aviation Forecasting, who explains: "Despite the modern computers, they are not able to model everything exactly. For example, we have to model the surface of the earth as well, and this has to be fed into the model. We have to take into account sea and land temperatures, the amount of moisture in the ground, the amount of rain that fell yesterday, and its effect, and vegetation. All these things have a role in the numerical mathematical equation of meteorology." The problem, to put it scientifically, is that there are too many variables. Chaos theory would have us believe that massive events such as hurricanes may originate in an almost indiscernible flickering of a butterfly's wings. There is a lot more at stake than failed picnics or forgetting your brolly. When you consider that the first human civilisations were the result of a gradual increase in temperature that forced people to congregate about river valleys, it becomes clear that predicting the weather over a prolonged period of time can help humanity to see where we've come from, and where we're headed.
Willy Shih of Silicon Graphics speaks to In Touch: "Typically when you think of solving a traditional supercomputing problem - predicting the weather, for example - a desktop system may take a month doing that calculation. A supercomputer will be able to predict the weather in a time that is relevant - in other words it doesn't do any good predicting tomorrow's weather but take a week doing it." If predicting the weather means talking to the Gods, then supercomputers are their messengers, translating the subtle shades of high-pressure systems and ocean currents into digital ones and zeros.
The increased speed of data delivery, coupled with a greater processing power means that highly detailed models can be built and tracked as they change over time. But will it lead to zero error in weather prediction? Sally asks Mike Edwards if we will ever see tomorrow's weather with absolute certainty. He answers: "In the short term we will find that the basic forecast will be almost computer generated. However, for the very important types of forecasting such as severe weather and the exact times that this occurs it is going to take immense work and knowledge from the new generation forecaster." (1.6) The weather gods still have a few surprises in store, but at least we can look them in the eye with a little more confidence. As computing power continues to develop and better measurement techniques are applied, the weather forecasts of the future will be more accurate. In time, we may even be able to map the changing contours of the global climate. That has huge implications for the study of agriculture and pollution. Any which way you look at it, talking about the weather just got a whole lot more interesting.
Contacts
Mike Haslam, Product Manager of Cray Products |
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However, this kind of exact prediction has remained as elusive as a butterfly, and weather forecasters have resembled nothing so much as butterfly-catchers with tiny, perforated nets. All that may be changing with the advent of supercomputers. Machines such as the CRAY, designed by a company called Silicon Graphics, are capable of processing such vast amounts of data that weather forecasting is entering a new era.
Mike Haslam of Cray Products explains: "The difference between a desktop computer and a supercomputer is one of capacity. It is the ability to be able to compute and move data around at very high speeds. For example, the very top of the range Cray Supercomputers are roughly 2000 times faster than your Pentium desktop computer. They have the capacity to move data around at thousands and thousands bytes per second - in fact we talk about gigabytes in terms of data transfer capacity inside a supercomputer, as opposed to megabytes in a desktop computer."
Supercomputers have such processing power that by synthesising meteorological information gathered from weather stations and satellites, they can construct 3-D animations of tomorrow's weather, today! The amount and variety of data that is collected is vast. In the past, this was all done manually, but with the arrival of the digital age, information can be transferred as quickly as it is gathered.
Mike Edwards continues: "Apart from the about 250 surface stations we have in South Africa, of which about 120 are fully automated, we also require data from our neighbouring countries, as well as from all over the rest of the world. In addition, we obtain data from island stations, ships, drifting and fixed buoys, and believe it or not, even from aircraft. We also require data from throughout the layers of the atmosphere, and therefore we have released upper air balloons which measure the atmosphere as they are sent through it."