1997-4 -- FOR IMMEDIATE RELEASE: February 5, 1997
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From January 13 through March 20, NASA-Lewis is flying a Twin Otter turboprop airplane equipped with measurement probes straight into treacherous icing zones identified by the NCAR team. NCAR scientists Ben Bernstein, Frank McDonough, and Marcia Politovich want to know whether their methods for forecasting these danger zones match up with the actual conditions pilots encounter in flight. NASA wants flight information to compare real-world ice shapes with those occurring in their experimental wind tunnel in Cleveland. "What's new and unique about this experiment is that it's specifically designed for large-droplet icing," says Politovich.
Bernstein and McDonough are also launching weather balloons in the Cleveland area from NCAR's instrumented weather van. The balloons carry sensing packages designed and built by Atek, Inc., of Boulder. The Atek sensors convey cloud structure data by measuring supercooled liquid as the balloons ascend through clouds.
Last year, at the request of the FAA, Bernstein created an algorithm, or mathematical problem-solving procedure, to automate freezing-drizzle advisories for areas smaller than those covered in general icing advisories. Due in large part to cooperative research by the AWC and NCAR, the areas of the advisories have become more specific over the past few years.
The research flights provide a good test of the new algorithm, which Bernstein calls the "stovepipe" because it uses data from observations on the ground to characterize what's happening in a stovepipe-shaped column of air at higher elevations. The experiment is also testing a new algorithm, developed by J. Vivekanandan of NCAR, that detects supercooled water droplets in cloud tops by examining infrared and visible-light readings from the GOES-8 satellite.
NASA-Lewis scientists will use flight data to improve icing simulation tools such as their icing research tunnel and their computer code for ice accretion, LEWICE. Working with AWC forecasters, the NCAR team will use the experiment's results to streamline pilot weather advisories issued at Kansas City.
Another step will be instructional materials for operational forecasters and pilots. Training modules, which include interactive CD-ROMs and Internet access, are being developed by the Cooperative Program for Operational Meteorology, Education and Training (COMET), a program of the University Corporation for Atmospheric Research. The modules will reach forecasters and pilots by mid-1998.
NCAR's icing research is sponsored by the National Science Foundation through an interagency agreement in response to requirements and funding by the Federal Aviation Administration's Aviation Weather Research Program. NCAR is managed by the University Corporation for Atmospheric Research.
|The ice-encrusted measurement probes above are mounted on the University of Wyoming's King Air research aircraft. According to the National Transportation Safety Board, from 1986 to 1996, U.S. general aviation, commuter, and air taxi flights (propeller-driven, turboprop, and small jet craft carrying 2-60 passengers) were involved in 315 accidents, including 225 fatalities, attributable to in-flight icing.|
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