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For more information on these science news and feature story tips, please contact the public information officer at the end of each item at (703) 292-8070. Editor: Bill Noxon Contents of this News Tip:
COASTAL GROWTH, NOT CLIMATE CHANGE, BLAMED FOR JUMP IN HURRICANE TOLLSIn the past eight years, three U.S. hurricanes--Andrew (1992), Hugo (1989) and Opal (1995)--combined to wreak over $40 billion in damage. A new study indicates that this number is not a reflection of unusual increases in hurricane strength or frequency. Rather it indicates that more and more Americans have put themselves and their property at risk by flocking to vulnerable coastal locations. This population shift could spell further trouble if hurricanes again make landfall as often as they did in the 1940s and 1960s, or if 1997 predictions of an active tropical storm season come true. Scientist Roger Pielke of the National Science Foundation (NSF)-supported National Center for Atmospheric Research in Boulder, Colorado, and his colleagues looked at landfalling hurricanes since 1925, and normalized their effects to 1995 values. Their analysis shows that seven hurricane seasons between 1940 and 1969 would have produced damages of more than $10 billion each, had they occurred in 1995. "It's only a matter of time before the nation experiences a $50 billion or greater storm, with multi-billion-dollar losses becoming increasingly frequent. Climate fluctuations that return the Atlantic to a period of more frequent storms will enhance the chances that this time will occur sooner rather than later," Pielke says. [Cheryl Dybas] SEAL DESIGN STUDIES YIELD GREAT LIP SERVICEThe next time you start your car or use any machine that works with hydraulics, purse your lips. That's much like the action of seals that hold fluid within, and provide essential lubrication, to engine crankshafts, transmissions, wheel assemblies, axle pinions and power steering systems. Almost every machine and appliance with fluid and a rotating shaft contains a lip seal that looks and works just as it sounds. Richard Salant, a mechanical engineer at Georgia Institute of Technology, is working to develop better tools to analyze and redesign these vital seals for more reliable, durable performance. Salant has created mathematical models to analyze air pockets that pepper the complex microlandscape of lubricating films on the surface of seals, and can calculate the maximum pressure a seal can contain. Jorn Larsen-Basse, who directs NSF's surface engineering & tribology program, says Salant's research has led to seals which have greatly helped reduce the environmental hazard of leaking oil from cars and machinery. Salant won the American Society of Mechanical Engineers' 1996 Henry R. Worthington Medal for his accomplishments and their potential benefits to industry. Salant credited two NSF grants which led him to his contributions and to the medal. [George Chartier] DO JET CONTRAILS FORECAST A CLOUDY CLIMATE?Can wispy plumes of jet exhaust affect climate? That's an emerging question on the radar screens of climatologists as more than 62 million commercial and military flights weave trails of jet exhaust across the skies above the U.S. each year. The short answer is that jet exhaust plumes--commonly referred to as contrails--can indeed influence regional climate, according to NSF-funded research by atmospheric scientist Steven Ackerman of the University of Wisconsin at Madison. Contrails are, in essence, a type of cloud formed by two parcels of air. There's warm, wet air from jet exhaust and the frigid air of the upper atmosphere. The resulting process is analogous to seeing your breath on a cold day. "It's been estimated that in certain heavy air traffic corridors, cloud cover has increased by as much as 20 percent," Ackerman says. Ackerman's research focused on questions of whether or not contrails are changing the chemistry of the upper atmosphere, and if they are responsible for increased regional cloud cover. Ackerman believes that if contrails do change the climate of a region, they do it indirectly by setting a series of events into motion. "We've got planes in the upper atmosphere and we're changing things. But how big is that effect? They're small clouds to begin with, but they grow and they can stay around for a long time." [Cheryl Dybas]
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