This newsletter is a joint project of SIRS Publishing, Inc. and the University Corporation for Atmospheric Research

Spring 2003— VOLUME 10, NO. 1

Copyright | Note to Teachers

Science and Safety: Reducing Winter Travel Hazards

It begins with a weather forecast. A prediction for colder temperatures and precipitation signals the likelihood of snow and ice accumulations that could cause potential travel delays or even greater impacts. Identifying when those hazards will occur and increasing the safety of travelers on the roads and in the air is the job of several scientists at the National Center for Atmospheric Research (NCAR) and its Research Applications Program (RAP) who are developing technologies to detect and manage icing conditions.

Safety on the Roads

After studying aviation icing for over a decade, NCAR is taking a look at how winter weather affects highway travel. (Photo © The Denver Post.)

Weather has an enormous impact on road transportation. With more cars on the nation¹s highways each day, more roads to keep clear, and more trucks on the roadways (according to the trucking industry, 80% of the freight within the U.S. is shipped via trucks), it is no surprise that Americans are highly dependent on good driving conditions. More than 17% of fatal crashes occur during inclement weather. Our economy is also affected. When cars and trucks cannot travel due to bad weather, many aspects of commerce are hindered. According to NCAR scientist Bill Mahoney, "If we can improve weather prediction and maintenance for our highways, the cost-benefit ratio for the national economy can be 10-to-1."

Although pilots have relied on weather forecasts for decades, predicting road weather - the effect of weather changes on road conditions - is a relatively new area. Today, NCAR scientists are working on a U.S. Department of Transportation-funded project called the winter road Maintenance Decision Support System (MDSS). This project aims to help agencies that maintain roads better gauge where and when to use various anti-icing and deicing methods. According to Mahoney, the MDSS project director, the project¹s goal is to build a prototype system that integrates weather and road data to improve prediction of weather conditions and identify highway segments that may be affected.

Figure 2: Transportation department managers are field testing the use of online MDSS real time data to predict and respond to winter road conditions.

The MDSS could help minimize the use of chemicals in treating roadways, which would be better for the environment, and it could save both time and resources. For example, the MDSS predicts the road condition for a particular stretch of road and then generates a recommended treatment plan for that road segment. This could involve plowing the road or applying solid salt, liquid magnesium chloride, or sand. The MDSS will also allow transportation managers to prepare for a variety of scenarios, such as unusually heavy traffic along a designated highway or a quick freeze-up of bridges and other elevated sections of road.

The MDSS creators are making software and documentation on the system available to the public in hopes that private-sector companies will use it to generate products that build on MDSS capabilities. A test of the MDSS is scheduled for locations in Des Moines and Ames, Iowa, from February to April 2003. Scientists from RAP and representatives from the Federal Highway Administration (FHA) will participate. Twenty-three other states have expressed strong interest in the program. Its success could pave the way for safer roads for all Americans.

Safety Before a Flight

Plane de-icing prior to departure (Photo by Carlye Calvin.)

Ice buildup affects aircraft under two circumstances: while a plane is readying for takeoff, and while the plane is in the air. Ice adhering to a plane¹s surface increases drag and decreases the lift available for aircraft to become and stay airborne. Research has found that as little as 0.003 inch (0.08 mm) of ice on a wing surface can increase drag and reduce airplane lift by as much as 25 percent. This is particularly dangerous during takeoff and landing, when lift and airspeed are critical to maintain a proper flight path off and onto airport runways. Several chemicals can be applied to aircraft to counteract icing. When wet, heavy snowfalls cause ice to accumulate on planes before takeoff, technicians apply a hot de-icing solution containing a glycol-based antifreeze. Then they apply a cold anti-icing fluid to extend the time that a de-iced aircraft will remain free of ice and snow. The chemicals at work in these de-icing and anti-icing substances are long-chain polymers whose viscous nature causes both snow and ice to melt and further inhibit future ice buildup. NCAR/RAP scientists Alan Hills and Scott Landolt use a laboratory cold room to test how various kinds of de-icing fluids perform under different temperatures and snowfall rates. They are striving to improve de-icing fluids as part of the certification process mandated by the Federal Aviation Administration (FAA).

Safety in the Air

CIP's Web-based data helps pilots idnetify ares of potential aircraft icing.

Better de-icing fluids are only one tool for avoiding in-flight icing, which can threaten smaller commuter planes and delay departures and landings of larger commercial aircraft. In 2002 researchers from NCAR, with funding from FAA, released an online system called CIP (Current Icing Potential). It provides high-precision maps, plots, and hourly updates to identify areas of potential aircraft icing produced by cloud droplets, freezing rain, and drizzle. CIP's Web-based display describes current icing conditions based on surface observations, numerical models, satellite and radar data, and pilot reports. "CIP helps dispatchers identify areas of potential icing so pilots can feel more confident about choosing a flight path," according to NCAR's Marcia Politovich, head of the FAA's In-Flight Icing Product Development Team.

Meet an Ice Expert

Marcia Politivich, NCAR/RAP Project Scientist

Marcia Politovich, a project scientist at NCAR/RAP, relies on her knowledge of the physics of icing as she continues to work to improve CIP¹s capabilities. Ultimately, her research, along with that of other NCAR scientists, will result in software that can detect and forecast icing conditions for all types of aircraft. Marcia says she was interested in science as far back in childhood as she can remember, encouraged by teachers and friends who shared her fascination. Initially, Marcia set her sights on stars and thought she would pursue a career in astronomy. As a physics major in college, working as an electronics technician, she was exposed to the atmospheric sciences. Marcia soon realized it was a research area that suited her interests, education, and abilities. Eventually, her studies led her to Dr. Phil Krider of the University of Arizona, a national expert on lightning, who would become her mentor. His love for his job and his willingness to share his passion for the science of weather with his students engages Marcia to this day. Marcia attributes much of her enthusiasm to variety in her job. Working to predict icing potential and severity requires that she participate in many different activities and interact with an assortment of professionals, from physicists to pilots to weather scientists. Cooperating with others gives Marcia the opportunity to view and value everyone¹s contribution. Her advice to students: "Keep your eyes open for what interests you. Watch for opportunities. Seek to find where you fit into the big picture."

Science Now is jointly published by the Walter Orr Roberts Institute at the University Corporation for Atmospheric Research and SIRS Publishing, Inc. (Social Issues Resources Series.) Science Now is published three times during the school year and is distributed to SIRS subscribers. Comments and questions should be directed to Joyce Gellhorn via Internet at jgellhorn@sprynet.com. You can also contact your SIRS representative or write to:

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