With the arrival of its first head, ICTP's Weather and Climate Group expects to rapidly expand its activities. The group plans to focus on long-term regional climate patterns and rely on sophisticated computer models to analyze these trends.

Change in Climate
at the Centre

Mudslides in southern Italy, prompted by torrential rainstorms, bury nearly 200 people. A searing heat wave in India leaves thousands dead. Tornadoes in the United States cut a destructive path across America's heartland killing hundreds of people and disrupting the lives of many more.

What's going on? Do these dramatic events represent random occurrences, or are they symptomatic of long-term alterations in global and regional climate patterns?

That's one of the critical issues that Filippo Giorgi and his colleagues will address in the years ahead. Giorgi joined the ICTP in May as the first head of the Centre's Weather and Climate Group.

"Our name reflects our broad areas of interest," says Giorgi. "Our research, however, will focus largely on climate."

For scientists, a clear distinction exists between weather and climate. Weather forecasting involves scientifically based predictions of temperatures, precipitation and cloud patterns over the next few days. Will it rain tomorrow? Will the weekend be sunny? When will the heat wave end? Climate studies, on the other hand, seek to explain long-range changes in global and regional climate patterns. Will average global temperatures rise in the future? What role do human activities play in the process? Must we prepare ourselves for more extreme weather events?

Giorgi notes that "The ICTP Weather and Climate Group won't be focusing its research on forecasting if it will rain on Tuesday. Instead, it will be studying the physical processes that affect our atmosphere, biosphere and oceans-and ultimately our climate and weather."

"I like to explain the distinction between weather and climate in this way," Giorgi adds. "Weather is something that farmers in the southern United States must pay attention to in order to see if they will need to protect their crops against an unexpected cold snap. Climate, on the other hand, is studied by atmospheric scientists trying to determine how long-term meteorological patterns will affect annual farm yields in Argentina and Ukraine."

Giorgi first became interested in climate and weather as a student at the University of L'Aquila in Italy. "I was born and raised in the small town of Sulmona about 120 kilometres east of Rome," notes Giorgi. "After my undergraduate studies, I was accepted to graduate school at Georgia Institute of Technology in the United States. After receiving my doctorate, I was hired by the National Centre for Atmospheric Research in Boulder, Colorado, where I worked for the 14 years before joining the ICTP."

"Our ability to forecast the weather in the short term-say the next three to five days-is now fairly accurate," explains Giorgi. "At the same time, although we have made some progress in our ability to predict if next spring will be relatively wet or warm, we still have a long way to go. And, when it comes to understanding potential climate changes over several decades, we've just touched the surface."

Giorgi's efforts at the National Center for Atmospheric Research focused on the development of computer models designed to improve our understanding of regional climate patterns.

"Until the late 1980s, scientists used global models of the atmosphere, which they labelled General Circulation Models (GCMs), to study the Earth's climate," Giorgi explains. "Such models have been instrumental in advancing our knowledge of the forces behind phenomena like global warming and El Niño. But they require tremendous computational resources and, as a result, their resolution is often coarse. Relatively small geographical areas-for example, islands, peninsulas and narrow mountain chains-are inadequately represented."

"To overcome this limitation," Giorgi says, "my colleagues and I turned to Limited Area Models (LAMs). These regional models attain much higher resolutions than GCMs. For this reason, they provide more detailed information on local and regional climate patterns. Put another way, LAMs zoom in and enhance the information provided by GCMs, allowing scientists to examine local and regional weather patterns that they may find of particular interest."

From the beginning, LAMs were used to predict short-term weather patterns and trace the path of such phenomena as cyclones and hurricanes. "My group in Colorado," notes Giorgi, "subsequently pushed LAMs onto a regional scale to develop what have come to be known as Regional Climate Models (RCMs)."

RCMs have helped fill the gap between local and global models. In effect, RCMs offer higher resolutions than global models and lengthier climatic time scales than their local counterparts. They have proven to be instrumental in regional studies examining the potential impact of such phenomena as climate change and El Niño. They have also been useful in analyzing the interactions of various aspects of the climate system, including the atmosphere and oceans.

And because RCMs focus on regions and require far less computing power than global models, they have proven to be particularly useful tools for scientists from developing countries who are interested in studying regional climate patterns and related environmental problems. "Our group," Giorgi observes, "will make LAMs available to scientists from developing countries and, more importantly, will provide the training and know-how necessary to use and understand these models."

"Geographically," says Giorgi, "ICTP's Weather and Climate Group will focus its attention on three areas of historic interest to the Centre: the Mediterranean; sub-Saharan Africa; and central and eastern Asia. These study areas are designed to allow us to make contributions to climate-related issues in both developing and developed countries. The Mediterranean is particularly interesting because it straddles a transition zone between arid and temperate climates."

Giorgi intends to pursue his goals through a variety of strategies. In addition to research and modelling activities, the group will host a summer school each year consisting of a two-week colloquium followed by a week-long conference. The group also plans to hold two annual workshops. Giorgi adds that his group will seek to create close ties with such leading meteorological research organizations as the Intergovernmental Panel on Climate Change (IPCC) and Global Change System for Analysis Research and Training (START). And it will pursue opportunities for outside funding to support research visits by young scientists from developing countries.

It's an ambitious agenda. To help him in his efforts, Giorgi has begun to put together his staff, which will consist of two senior scientists (including himself); a part-time senior visiting scientist (Serbian-born Fedor Mesinger who works with the U.S. National Weather Service); two post docs; and two support scientists. "The unfilled positions have already been advertised and a number of excellent candidates have applied," Giorgi says. "We hope to have all staff members in place by the end of the year."

"What makes the study of climate more interesting-and more complicated-than ever," observes Giorgi, "is that we have come to realize that meteorology entails more than enhancing our understanding of the atmosphere. Weather and climate are effected by land use patterns, vegetation, topography, pollution, radiation, ocean currents and a whole host of factors that not too long ago never entered into our analyses. That's why scientists increasingly talk about climate systems and not simply climate."

"No pun intended, weather and climate are hot topics," Giorgi notes with a sly smile. "Regional Climate Models, which stand at the juncture between Global Circulation Models and Local Area Models, are viewed as one of the most promising areas of study for improving our understanding of climate patterns. The ICTP has an opportunity to make important contributions to this effort. And that's what we hope to do in the months and years ahead."

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