PERSPECTIVES
F YOU have ever listened to the weather forecast and handle the scale of computing required.
I
wondered how they work out whether it’s going to rain or That dream came true in the form of ENIAC (Electronic
shine, then Professor Peter Lynch is the man to ask. We meet Numerical Integrator And Computer), a supercomputer in the US
on a suitably blustery day at his office in UCD’s Meteorology that in the 1950s ground through the numbers needed to predict
and Climate Centre, in the School of Mathematical Sciences. changes in the weather. Since then, our increased understanding
Storm and flood warnings saturate the weekend’s news of the atmosphere combined with better data and computing
bulletins, providing a good example of how socially important power has added a day per decade to the range of reliable short-
weather forecasting is, according to Lynch, UCD Professor of term forecasts, according to Lynch.
Meteorology. We can now predict weather events like storms within three to
“The fact that people can be warned a couple of days in four days with reasonable confidence, he says. But it requires
advance so they can get the sandbags out and take precautions, some clever thinking. The atmosphere is chaotic or non-linear,
this has enormous benefit for society,” he says. “The increased which in practice means that even tiny changes in the system can
skill of forecasts and their reliability has huge social benefits: for quickly grow into big differences. So the best approach to
agriculture, transport, fisheries and forestry. In fact, just about forecasting is to do an ‘ensemble’ of 50 to 100 predictions, each
everything is affected by the weather.” one looking at a plausible set of initial conditions.
The complexity of the atmosphere means a huge amount of Looking at multiple scenarios helps to uncover the relative
number-crunching is involved in forecasting, and this is where probabilities of weather outcomes, explains Lynch. “They tend to
Lynch sees the beauty of it. A maths graduate from UCD, he cluster into groups, some saying it will be windy next week, with
discovered an affinity for numbers thanks in part to one of his others saying it will be calm. We can group them and then
lecturers, Dr David Judge. “His lectures in mechanics had an depending on the relative number of forecasts in each cluster, we
electrifying effect, I thought they were terrific. He really instilled have an idea of the likelihood of the outcome.”
a great love of the subject and I have been passionate about However, there are limitations. “You can’t predict the details
mathematics ever since.” beyond, say, a couple of weeks,” he says. “So if you plan on
Lynch completed a master’s degree at UCD and then joined Met getting married in three months’ time and you want to know if
Éireann where he spent three decades as a forecaster, including a the particular Saturday is going to be fine, we can’t tell. It’s the
few years at Shannon Airport. “I’m happy to say no planes fundamental nature of the system that it is extremely sensitive to
crashed while I was doing that,” he laughs. little variations.”
He did a PhD at Trinity College Dublin, then became head of For fun, Lynch reprocessed the original ENIAC forecast data on
research and eventually deputy director at Met Éireann. It was in a laptop. The procedure that took a full day in the 1950s was
this position that he had responsibility for training sewn up in less than a second. He then teamed up with his son
meteorologists. It was an area where the organisation saw a Owen, a software engineer, to put the forecasting function onto
glaring gap in home-grown education, so Met Éireann and UCD his mobile phone.
set up a memorandum of understanding for education and To demonstrate, Lynch grabs his phone, selects the function
research. Lynch was appointed the first Chair of Meteorology in and within three quarters of a second we have a weather forecast
UCD in 2004 and he now oversees undergraduate and taught for North America. “It’s not a telephone any more, it’s a portable,
master’s programmes, as well as postgraduate research in the hand-operated numerical integrator and computer, which gives
university. you Phoniac,” he smiles.
That research includes modelling wind variability in Ireland – So could we all have forecasts on our mobiles in years to come?
an important area for developing alternative energy sources – “Why not?” says Lynch, outlining his own dream of the future.
looking at atmospheric turbulence and figuring out how to deal “You could imagine a yachtsman modelling large eddies as he
with mathematical noise in weather forecast models. sailed around Dún Laoghaire. Perhaps Phoniac will be the
Lynch also has a deep interest in the history of numerical forerunner of such microscale forecasting systems, just as ENIAC
forecasting, and wrote a book on the early 20th-century pioneer foreshadowed global and regional weather predictions.”
Lewis Fry Richardson, who challenged the traditional approach of
basing weather predictions on what had gone before.
Claire O’Connell (BSc in Botany ’92, PhD in Pharmacology ’98) is
Richardson’s attempts at a trial forecast were hampered by a lack
a freelance journalist and frequent contributor to The Irish
of understanding about the atmosphere, but he helped pave the
Times and The Irish Examiner. She is currently completing a
way for modern forecasting and dreamt of a day when we could Masters in Science Communication at Dublin City University.
UCD CONNECTIONS PAGE FORTY SEVEN
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