Roger Daley

Atmospheric Science

Principal constructor of the Canadian numerical weather forecasting system

"Don’t worry if you have not made a choice of career. It can come anytime from grade school to graduate school. But for a career in the natural sciences get a good foundation in math."

Meteorology is the study of Earth’s atmosphere and weather. If you ever listen to a weather forecast, chances are that you are enjoying the results of Roger Daley’s research. Among many other accomplishments, he developed a mathematical technique called spherical harmonic expansion that is now used worldwide in computerized global atmospheric simulation models to predict the weather.

Just as people make small plastic or wooden models of cars or airplanes, meteorologists make models of how the temperature, wind, rain and other things in the atmosphere change over time and space. Instead of plastic and wood, meteorologists use numbers and equations inside a computer to model the real atmosphere. It’s very similar to a car-racing video game. The simulated cars and the feeling of racing them can be very detailed and intense, but it’s not a real car in a real race. In fact, it’s just a bunch of mathematical calculations done by the computer and displayed on a screen. Yet by playing the game a person can get an idea of what it would be like to drive a real race car. In the same way, the atmospheric models used by meteorologists are not real, but they give an idea of what the real atmosphere might be like under certain conditions. Daley’s models are used every day to collect weather data and predict the weather all over the world. Good weather forecasts are essential for agriculture and all forms of transportation, among many other human endeavours.

Daley’s models are also used in studies of global warming — the conjecture that burning coal, oil and gas might generate a large enough increase in carbon dioxide over the next 100 years to cause a greenhouse effect, warming the planet by a few degrees Centigrade. Ice caps would melt and the ocean would rise, drastically changing the world as we know it. Although he served on the IPCC, Daley remained somewhat skeptical about the potential for global warming. He felt there were too many unknown variables and many questions that had not been considered. He was surprised by the amount of public attention the IPCC report generated when it warned about global warming, and he felt it was an overreaction. He was cynical about the many world governments who made a big show of reducing greenhouse emissions while, for economic reasons, they had no intention of ever doing so. He was also critical of the huge number of pseudo-scientists who suddenly became “experts” on global warming after the release of the IPCC report. For this reason, Daley resigned from the IPCC and dissociated himself from global-warming research.

He said, in his very well-educated opinion as the scientist who created global atmospheric modelling: “Our systems cannot predict weather much beyond four days, so attempting to predict global changes 100 years from now seems questionable at best.”


Weather satellite. Click to enlarge.

1. Real Earth Earth’s weather is a very complex system affected by ocean currents, temperature, pressure, wind and many other factors.

2. Weather satellite Several hundred weather and remote sensing satellites currently orbit Earth, detecting many of the factors that create weather. They send this information back to base stations that relay it to weather computers.

3. Supercomputer A supercomputer in a central location records and interprets information from satellites and other sources, updating itself continuously as more and more data come in.

4. Model Earth The weather computer constructs a model of Earth based on very complicated mathematical formulas. This model is updated all the time and is used to generate maps that are sent to weather forecasters. They use these maps to help predict the weather.

The process of combining data in the model with data from real-world observations is called data assimilation, and this was Daley’s specialty. According to his colleagues in Monterey, he was equally productive and comfortable writing low-level computer code components of weather-modelling systems or working out the abstract matrix algebra of data assimilation theory.


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Daley hoped future generations would develop a huge computer system that would be able to model all the geophysical systems in the world. (Geophysical systems are the forces and motions that affect Earth’s air, lakes and oceans and even continents through earthquakes and volcanoes.) Among other things, such a system would allow us to accurately predict trends in global warming and the formation of ozone holes, gaps in the upper atmosphere that appear seasonally over the North and South Polar ice caps.

Explore Further

Roger Daley, Atmospheric Data Analysis, Cambridge University Press, 1991.

Daley Memorial web page at the U.S. Naval Research Laboratory.

Environment Canada radar and satellite images:

U.S. National Weather Service. Click on tabs for satellite and radar images

Weather Underground has international weather maps and data.


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