New Faculty Profile: Roni Avissar

Roni Avissar, the Pratt School's new chair of civil and environmental engineering, wants to teach astronauts.

And not just any astronauts, but true space pioneers - men and women who will someday lead missions to Mars, live on the Moon, spend years in the international space station.

Given the pace of technological development and the rising average age of mission commanders, Avissar figures these future explorers are in high school right now. This means it's about time for them to start thinking about college - more specifically, Duke.

"If you look at the major problems of space exploration, you'll see that structure and environment are the real difficulty," Avissar explained. "I think mission commanders will need a background in civil and environmental engineering. I want to recruit those people and bring them to Duke."

Recruiting astronauts is hardly a typical goal for a new chairman, but Avissar is no typical engineer. Although his field of expertise - environmental fluid dynamics - is a standard discipline in modern engineering, Avissar's previous po sition was in Rutgers' Department of Environmental Science, not its engineering school. Twelve years in an environmental science department brought him in contact with ideas not necessarily emphasized in traditional engineering programs, he said.

At Rutgers, Avissar focused on creating computer models of how the Earth's atmosphere, oceans and land interact to make weather and climate. One of his most recent projects used such models to explore the effects of rainforest destruction on the Earth's water cycle.

Scientists have known for years that living trees channel moisture from the soil into the atmosphere, a process called evapotranspiration. Cut down the rainforest, and the amount of water in the atmosphere above the tropics will drop. Due to the complexity of the Earth's atmosphere, however, it is difficult to predict what such a drop will do to the rest of the planet - and even harder to explain why.

As an analogy, Avissar cited the El Niño phenomenon, in which an increase in ocean temperature off the coast of Chile can cause catastrophic droughts and floods in far-flung corners of the planet.

Avissar's simulations showed that a drop in atmospheric water content during the southern summer - January and February - results in lower rainfall in the northern hemisphere six months later, during prime growing season on the American Great Plains. The mechanism for such "teleconnec-tion" is not well understood, but Avissar believes that the six-month lag time is significant.

The atmosphere, he notes, has a "memory" of only a few days. When something disturbs it, the direct effects of that disturbance die out very quickly. Oceans, by contrast, have memories of decades or centuries.

According to Avissar, the soil, with a memory of up to a year, has the ability to create the time lag needed to explain the teleconnec-tion between rainforest destruction and farm droughts.

As chairman of civil and environmental engineering, one of Avissar's first and most important projects will be to persuade other highly qualified professors to join him. He hopes to hire six to 10 new faculty over the next few years.

"Very few schools in the world are on the move as much as Duke is in engineering right now," he said. "I felt that by coming here, I could participate in something really great."

Avissar also plans to teach an undergraduate course next spring on environmental transport phenomena and turbulence. He looks forward to working with undergraduate engineers, he said, in part because he believes engineering students are better prepared to learn and do research in atmospheric, land and oceanic modeling.

The high potential and rigorous background of Duke students, plus a "tremendous energy" in the Pratt School, were key factors in his decision to come to Duke, he said.

On the scientific side, Avissar's latest project idea involves using a helicopter-based platform for collecting atmospheric data. Usually, scientists take atmospheric data with weather balloons or in special planes packed with instruments that scoop up air samples and take measurements. However, neither system has the flexibility of a helicopter, which can hover in one place, skim just above the ocean waves and take off from the deck of a medium-sized research ship.

The challenge is to develop a system that is not affected by the turbulence caused by downwash from the helicopter's rotors. Such an effort would likely involve not only members of his own department, but also faculty and students from the mechanical and electrical engineering disciplines, Avissar said.

In addition, Avissar intends to fly the helicopter. He's a commercial chopper pilot, and he said he enjoys the flying aspect almost as much as the research.

"When people ask me what my hobby is, I tell them it's my work. I have lots of fun doing work generally - and if I get to fly while doing it, that's even better."