June 7, 1999 BOULDER -- Starting June 2, the National Center for Atmospheric Research (NCAR) is helping guide three research aircraft into Colorado thunderstorms to test how well an airborne Doppler weather radar can detect convective turbulence. The aircraft will fly from the Ft. Collins-Loveland Jet Center to zero in on storms from Ft. Collins to Cheyenne, Wyoming, June 2-18.
The Colorado turbulence research experiment is part of the National Aeronautics and Space Administration's Aviation Safety Program. Other partners are the National Science Foundation (NSF), AlliedSignal, Rockwell Collins, Colorado State University, and the South Dakota School of Mines and Technology. NSF is NCAR's primary sponsor.
AlliedSignal will test its airborne weather radar aboard a company-owned Convair 580 while Rockwell-Collins tests its own similar radar aboard its Sabreliner. Both planes will record the aircraft's response to turbulence, such as accelerations and attitudes. An armored T-28 storm- penetration aircraft operated by the South Dakota School of Mines and Technology will gather both atmospheric and airplane-response data as it flies into the storm ahead of the other two. Its pilot will report on lightning, hail, and turbulence to the Convair and Sabreliner pilots as the three search for pockets of turbulence while skirting areas of heavy rain and hail. All three planes will fly nearly every afternoon that storms and turbulence are present.
On the ground, Colorado State University will operate two Doppler radars to locate storms and verify aircraft data. CSU researchers and their NSF-sponsored summer students will gather the ground radar data from sites near Greeley and the Pawnee National Grassland. Sounding balloons launched from NCAR's mobile weather van will measure temperature, pressure, humidity, and winds.
NCAR atmospheric scientist Larry Cornman will guide daily operations. Says Cornman, "Airborne Doppler radar is a promising tool for detecting convective turbulence. If everything goes well, it could be ready for use by U.S. airlines within two years." Onboard Doppler radars are already detecting low-level wind shear from commercial planes. Cornman will develop the mathematical equations that will make the standard weather radar data useful for detecting convective turbulence.
Convective turbulence is associated with storms and clouds. It can rip sections off small planes and injure crew and passengers aboard larger craft. Up to 60% of aircraft encounters with turbulence is due to turbulence associated with thunderstorms. Poor forecasting and detection of all kinds of turbulence cost U.S. airlines $100 million each year in injuries and disrupted operations.
Convective turbulence may be detected by weather radars that bounce radio waves off large raindrops, snowflakes, and hailstones. To detect clear-air turbulence, which occurs in the absence of clouds, scientists have experimented with lidars, which reflect laser beams off tiny moving particles invisible to the radar.
In 1996 the White House established a Commission on Aviation Safety and Security. As a result, the Federal Aviation Administration and NASA Aviation Safety Programs were instituted. One element of these safety programs is reduction of injuries from aircraft encounters with atmospheric turbulence.
NCAR is managed by the University Corporation for Atmospheric Research, a consortium of more than 60 universities offering Ph.D.s in atmospheric and related sciences.
Note to Editors: Reporters may fly on AlliedSignal's Convair 580 on a space-available basis. Flights will be decided at a noon weather briefing on the same day.
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